diff --git a/src/blackmisc/avaircraft.cpp b/src/blackmisc/avaircraft.cpp
index c22ba7609..eb35a6291 100644
--- a/src/blackmisc/avaircraft.cpp
+++ b/src/blackmisc/avaircraft.cpp
@@ -124,15 +124,32 @@ namespace BlackMisc
             return BlackMisc::calculateHash(hashs, "CAircraft");
         }
 
+        /*
+         * metaTypeId
+         */
+        int CAircraft::getMetaTypeId() const
+        {
+            return qMetaTypeId<CAircraft>();
+        }
+
+        /*
+         * is a
+         */
+        bool CAircraft::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CAircraft>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
         /*
          * Compare
          */
-        int CAircraft::compare(const QVariant &qv) const
+        int CAircraft::compareImpl(const CValueObject &otherBase) const
         {
-            Q_ASSERT(qv.canConvert<CAircraft>());
-            Q_ASSERT(!qv.isNull() && qv.isValid());
-            CAircraft aircraft = qv.value<CAircraft>();
-            return this->getCallsign().compare(aircraft.getCallsign());
+            const auto &other = static_cast<const CAircraft &>(otherBase);
+
+            return this->getCallsign().asString().compare(other.getCallsign().asString(), Qt::CaseInsensitive);
         }
 
         /*
diff --git a/src/blackmisc/avaircraft.h b/src/blackmisc/avaircraft.h
index ec0de50e9..df248cd36 100644
--- a/src/blackmisc/avaircraft.h
+++ b/src/blackmisc/avaircraft.h
@@ -278,11 +278,6 @@ namespace BlackMisc
              */
             virtual uint getValueHash() const;
 
-            /*!
-             * \copydoc BlackObject::compare
-             */
-            virtual int compare(const QVariant &qv) const;
-
             /*!
              * \brief Register metadata
              */
@@ -337,6 +332,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/avaircrafticao.cpp b/src/blackmisc/avaircrafticao.cpp
index f5ea876c0..4609465e4 100644
--- a/src/blackmisc/avaircrafticao.cpp
+++ b/src/blackmisc/avaircrafticao.cpp
@@ -1,5 +1,6 @@
 #include "avaircrafticao.h"
 #include "blackmisc/blackmiscfreefunctions.h"
+#include <tuple>
 
 namespace BlackMisc
 {
@@ -19,6 +20,39 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CAircraftIcao::getMetaTypeId() const
+        {
+            return qMetaTypeId<CAircraftIcao>();
+        }
+
+        /*
+         * is a
+         */
+        bool CAircraftIcao::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CAircraftIcao>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CAircraftIcao::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CAircraftIcao &>(otherBase);
+
+            const auto lhs = std::tie(this->m_designator, this->m_color, this->m_airline, this->m_livery);
+            const auto rhs = std::tie(other.m_designator, other.m_color, other.m_airline, other.m_livery);
+
+            if (lhs < rhs) { return -1; }
+            if (lhs > rhs) { return 1; }
+            return 0;
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/avaircrafticao.h b/src/blackmisc/avaircrafticao.h
index 7011fcc57..046cd2167 100644
--- a/src/blackmisc/avaircrafticao.h
+++ b/src/blackmisc/avaircrafticao.h
@@ -214,6 +214,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/avaircraftsituation.cpp b/src/blackmisc/avaircraftsituation.cpp
index aae2813b1..c0febe914 100644
--- a/src/blackmisc/avaircraftsituation.cpp
+++ b/src/blackmisc/avaircraftsituation.cpp
@@ -23,6 +23,33 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CAircraftSituation::getMetaTypeId() const
+        {
+            return qMetaTypeId<CAircraftSituation>();
+        }
+
+        /*
+         * is a
+         */
+        bool CAircraftSituation::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CAircraftSituation>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CAircraftSituation::compareImpl(const CValueObject &/*otherBase*/) const
+        {
+            qFatal("not implemented");
+            return 0;
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/avaircraftsituation.h b/src/blackmisc/avaircraftsituation.h
index b27603fe1..068d1275e 100644
--- a/src/blackmisc/avaircraftsituation.h
+++ b/src/blackmisc/avaircraftsituation.h
@@ -233,6 +233,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/avaltitude.cpp b/src/blackmisc/avaltitude.cpp
index 789d2447b..fd932668d 100644
--- a/src/blackmisc/avaltitude.cpp
+++ b/src/blackmisc/avaltitude.cpp
@@ -58,26 +58,36 @@ namespace BlackMisc
             return !((*this) == other);
         }
 
+        /*
+         * metaTypeId
+         */
+        int CAltitude::getMetaTypeId() const
+        {
+            return qMetaTypeId<CAltitude>();
+        }
+
+        /*
+         * is a
+         */
+        bool CAltitude::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CAltitude>()) { return true; }
+
+            return this->CLength::isA(metaTypeId);
+        }
+
         /*
          * Compare
          */
-        int CAltitude::compare(const QVariant &qv) const
+        int CAltitude::compareImpl(const CValueObject &otherBase) const
         {
-            Q_ASSERT(qv.canConvert<CAltitude>() || qv.canConvert<CLength>());
-            Q_ASSERT(qv.isValid() && !qv.isNull());
-            if (qv.canConvert<CAltitude>())
-            {
-                CAltitude other = qv.value<CAltitude>();
-                if (this->isMeanSeaLevel() && other.isAboveGroundLevel()) return 1;
-                if (this->isAboveGroundLevel() && other.isMeanSeaLevel()) return -1;
-                return this->compare(other);
-            }
-            else if (qv.canConvert<CLength>())
-            {
-                return this->compare(qv.value<CLength>());
-            }
-            qFatal("Invalid comparison");
-            return 0; // just for compiler
+            const auto &other = static_cast<const CAltitude &>(otherBase);
+
+            if (this->isMeanSeaLevel() && other.isAboveGroundLevel()) { return 1; }
+            if (this->isAboveGroundLevel() && other.isMeanSeaLevel()) { return -1; }
+            if (*this < other) { return -1; }
+            if (*this > other) { return 1; }
+            return 0;
         }
 
         /*
diff --git a/src/blackmisc/avaltitude.h b/src/blackmisc/avaltitude.h
index 8a957c92a..48b79682d 100644
--- a/src/blackmisc/avaltitude.h
+++ b/src/blackmisc/avaltitude.h
@@ -39,6 +39,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
@@ -122,17 +137,6 @@ namespace BlackMisc
                 return m_datum;
             }
 
-            /*!
-             * \copydoc BlackObject::compare
-             */
-            virtual int compare(const QVariant &qv) const;
-
-            /*!
-             * \todo this is a hack, to avoid hiding inherited names in CPhysicalQuantity
-             * (see Effective C++ item 33) CPhysicalQuantity::compare is the real culprit
-             */
-            int compare(const CLength &other) const { return static_cast<const CLength *>(this)->compare(other); }
-
             /*!
              * \brief Register metadata
              */
diff --git a/src/blackmisc/avatcstation.cpp b/src/blackmisc/avatcstation.cpp
index e5d8d05e9..42c30bcf4 100644
--- a/src/blackmisc/avatcstation.cpp
+++ b/src/blackmisc/avatcstation.cpp
@@ -429,15 +429,32 @@ namespace BlackMisc
             }
         }
 
+        /*
+         * metaTypeId
+         */
+        int CAtcStation::getMetaTypeId() const
+        {
+            return qMetaTypeId<CAtcStation>();
+        }
+
+        /*
+         * is a
+         */
+        bool CAtcStation::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CAtcStation>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
         /*
          * Compare
          */
-        int CAtcStation::compare(const QVariant &qv) const
+        int CAtcStation::compareImpl(const CValueObject &otherBase) const
         {
-            Q_ASSERT(qv.canConvert<CAtcStation>());
-            Q_ASSERT(!qv.isNull() && qv.isValid());
-            CAtcStation atc = qv.value<CAtcStation>();
-            return this->getCallsign().compare(atc.getCallsign());
+            const auto &other = static_cast<const CAtcStation &>(otherBase);
+
+            return this->getCallsign().asString().compare(other.getCallsign().asString(), Qt::CaseInsensitive);
         }
 
         /*
diff --git a/src/blackmisc/avatcstation.h b/src/blackmisc/avatcstation.h
index 801411ec7..7c93e8648 100644
--- a/src/blackmisc/avatcstation.h
+++ b/src/blackmisc/avatcstation.h
@@ -453,11 +453,6 @@ namespace BlackMisc
              */
             static void registerMetadata();
 
-            /*!
-             * \copydoc BlackObject::compare
-             */
-            virtual int compare(const QVariant &qv) const;
-
         protected:
             /*!
              * \brief Meaningful string representation
@@ -466,6 +461,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/avcallsign.cpp b/src/blackmisc/avcallsign.cpp
index 5dbc48f72..460f871ab 100644
--- a/src/blackmisc/avcallsign.cpp
+++ b/src/blackmisc/avcallsign.cpp
@@ -98,21 +98,31 @@ namespace BlackMisc
         }
 
         /*
-         * Compare
+         * metaTypeId
          */
-        int CCallsign::compare(const QVariant &qv) const
+        int CCallsign::getMetaTypeId() const
         {
-            Q_ASSERT(qv.canConvert<CCallsign>());
-            Q_ASSERT(!qv.isNull() && qv.isValid());
-            return this->compare(qv.value<CCallsign>());
+            return qMetaTypeId<CCallsign>();
+        }
+
+        /*
+         * is a
+         */
+        bool CCallsign::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CCallsign>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
         }
 
         /*
          * Compare
          */
-        int CCallsign::compare(const CCallsign &callsign) const
+        int CCallsign::compareImpl(const CValueObject &otherBase) const
         {
-            return this->m_callsign.compare(callsign.asString(), Qt::CaseInsensitive);
+            const auto &other = static_cast<const CCallsign &>(otherBase);
+
+            return this->m_callsign.compare(other.asString(), Qt::CaseInsensitive);
         }
 
         /*
diff --git a/src/blackmisc/avcallsign.h b/src/blackmisc/avcallsign.h
index 538466cdb..b237b4fca 100644
--- a/src/blackmisc/avcallsign.h
+++ b/src/blackmisc/avcallsign.h
@@ -121,17 +121,6 @@ namespace BlackMisc
              */
             virtual uint getValueHash() const;
 
-            /*!
-             * \copydoc BlackObject::compare
-             */
-            virtual int compare(const QVariant &qv) const;
-
-            /*!
-             * Compare with other callsign
-             * \return
-             */
-            virtual int compare(const CCallsign &callsign) const;
-
             /*!
              * \brief Register metadata
              */
@@ -145,6 +134,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/avinformationmessage.cpp b/src/blackmisc/avinformationmessage.cpp
index 26efcdfa5..be9a3324d 100644
--- a/src/blackmisc/avinformationmessage.cpp
+++ b/src/blackmisc/avinformationmessage.cpp
@@ -13,6 +13,36 @@ namespace BlackMisc
             return this->m_message;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CInformationMessage::getMetaTypeId() const
+        {
+            return qMetaTypeId<CInformationMessage>();
+        }
+
+        /*
+         * is a
+         */
+        bool CInformationMessage::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CInformationMessage>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CInformationMessage::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CInformationMessage &>(otherBase);
+
+            if (this->m_type < other.m_type) { return -1; }
+            if (this->m_type > other.m_type) { return 1; }
+            return this->m_message.compare(other.m_message);
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/avinformationmessage.h b/src/blackmisc/avinformationmessage.h
index f04484299..6a2db3acf 100644
--- a/src/blackmisc/avinformationmessage.h
+++ b/src/blackmisc/avinformationmessage.h
@@ -164,6 +164,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/aviobase.h b/src/blackmisc/aviobase.h
index 1cac99ccd..160503b44 100644
--- a/src/blackmisc/aviobase.h
+++ b/src/blackmisc/aviobase.h
@@ -58,6 +58,26 @@ namespace BlackMisc
                 return this->m_name == other.m_name;
             }
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const { return 0; }
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const { return this->CValueObject::isA(metaTypeId); }
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const
+            {
+                Q_UNUSED(other);
+                qFatal("not implemented");
+                return 0;
+            }
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/blackmiscfreefunctions.cpp b/src/blackmisc/blackmiscfreefunctions.cpp
index 49abec738..2e70c2ac3 100644
--- a/src/blackmisc/blackmiscfreefunctions.cpp
+++ b/src/blackmisc/blackmiscfreefunctions.cpp
@@ -221,7 +221,7 @@ int BlackMisc:: compareQVariants(const QVariant &v1, const QVariant &v2)
         const CValueObject *cs2 = CValueObject::fromQVariant(v2);
         if (cs1 && cs2)
         {
-            return cs1->compare(v2); // Note, that I have to compare against QVariant
+            return compare(*cs1, *cs2);
         }
     }
 
diff --git a/src/blackmisc/containerbase.h b/src/blackmisc/containerbase.h
index 299581fa8..df6052cd2 100644
--- a/src/blackmisc/containerbase.h
+++ b/src/blackmisc/containerbase.h
@@ -152,6 +152,36 @@ namespace BlackMisc
             return str += "}";
         }
 
+        /*!
+         * \copydoc CValueObject::getMetaTypeId
+         */
+        virtual int getMetaTypeId() const { return qMetaTypeId<C<T>>(); }
+
+        /*!
+         * \copydoc CValueObject::isA
+         */
+        virtual bool isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<C<T>>()) { return true; }
+            return CValueObject::isA(metaTypeId);
+        }
+
+        /*!
+         * \copydoc CValueObject::compareImpl
+         */
+        virtual int compareImpl(const CValueObject &/*other*/) const
+        {
+            //const auto &o = static_cast<const CContainerBase &>(other);
+            //if (derived().size() < o.derived().size()) { return -1; }
+            //if (derived().size() > o.derived().size()) { return 1; }
+            //for (auto i1 = derived().begin(), i2 = o.derived().begin(); i1 != derived().end() && i2 != o.derived().end(); ++i1, ++i2)
+            //{
+            //    if (*i1 < *i2) { return -1; }
+            //    if (*i1 > *i2) { return 1; }
+            //}
+            return 0;
+        }
+
         virtual void marshallToDbus(QDBusArgument &argument) const
         {
             argument.beginArray(qMetaTypeId<T>());
diff --git a/src/blackmisc/coordinategeodetic.cpp b/src/blackmisc/coordinategeodetic.cpp
index ef6914f05..e3f09db00 100644
--- a/src/blackmisc/coordinategeodetic.cpp
+++ b/src/blackmisc/coordinategeodetic.cpp
@@ -25,6 +25,38 @@ namespace BlackMisc
             return s.arg(this->m_latitude.valueRoundedWithUnit(6, i18n)).arg(this->m_longitude.valueRoundedWithUnit(6, i18n)).arg(this->m_height.valueRoundedWithUnit(i18n));
         }
 
+        /*
+         * metaTypeId
+         */
+        int CCoordinateGeodetic::getMetaTypeId() const
+        {
+            return qMetaTypeId<CCoordinateGeodetic>();
+        }
+
+        /*
+         * is a
+         */
+        bool CCoordinateGeodetic::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CCoordinateGeodetic>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CCoordinateGeodetic::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CCoordinateGeodetic &>(otherBase);
+
+            int cmp = compare(this->m_latitude, other.m_latitude);
+            if (cmp) { return cmp; }
+            cmp = compare(this->m_longitude, other.m_longitude);
+            if (cmp) { return cmp; }
+            return compare(this->m_height, other.m_height);
+        }
+
         /*
          * Marshall to Dbus
          */
diff --git a/src/blackmisc/coordinategeodetic.h b/src/blackmisc/coordinategeodetic.h
index 6c9efab22..9354d668d 100644
--- a/src/blackmisc/coordinategeodetic.h
+++ b/src/blackmisc/coordinategeodetic.h
@@ -82,6 +82,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus
              * \param argument
diff --git a/src/blackmisc/geoearthangle.cpp b/src/blackmisc/geoearthangle.cpp
index 7ddcf9553..23e769793 100644
--- a/src/blackmisc/geoearthangle.cpp
+++ b/src/blackmisc/geoearthangle.cpp
@@ -71,17 +71,34 @@ namespace BlackMisc
             return LATorLON(a);
         }
 
+        /*
+         * metaTypeId
+         */
+        template <class LATorLON> int CEarthAngle<LATorLON>::getMetaTypeId() const
+        {
+            return qMetaTypeId<LATorLON>();
+        }
+
+        /*
+         * is a
+         */
+        template <class LATorLON> bool CEarthAngle<LATorLON>::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<LATorLON>()) { return true; }
+
+            return this->CAngle::isA(metaTypeId);
+        }
+
         /*
          * Compare
          */
-        template <class LATorLON> int CEarthAngle<LATorLON>::compare(const QVariant &qv) const
+        template <class LATorLON> int CEarthAngle<LATorLON>::compareImpl(const CValueObject &otherBase) const
         {
-            Q_ASSERT(qv.canConvert<LATorLON>() || qv.canConvert<CAngle>());
-            Q_ASSERT(qv.isValid() && !qv.isNull());
-            if (qv.canConvert<LATorLON>())
-                return this->compare(qv.value<LATorLON>());
-            else
-                return this->compare(qv.value<CAngle>());
+            const auto &other = static_cast<const LATorLON &>(otherBase);
+
+            if (*this < other) { return -1; }
+            else if (*this > other) { return 1; }
+            else { return 0; }
         }
 
         // see here for the reason of thess forward instantiations
diff --git a/src/blackmisc/geoearthangle.h b/src/blackmisc/geoearthangle.h
index 891263f97..c17b5c010 100644
--- a/src/blackmisc/geoearthangle.h
+++ b/src/blackmisc/geoearthangle.h
@@ -45,6 +45,21 @@ namespace BlackMisc
                 return this->valueRoundedWithUnit(BlackMisc::PhysicalQuantities::CAngleUnit::deg(), 6, i18n);
             }
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
@@ -175,20 +190,6 @@ namespace BlackMisc
                 return l;
             }
 
-            /*!
-             * Compare
-             */
-            int compare(const QVariant &qv) const;
-
-            /*!
-             * \todo this is a hack, to avoid hiding inherited names in CPhysicalQuantity
-             * (see Effective C++ item 33) CPhysicalQuantity::compare is the real culprit
-             */
-            int compare(const CEarthAngle &other) const
-            {
-                return static_cast<const CPhysicalQuantity<BlackMisc::PhysicalQuantities::CAngleUnit, BlackMisc::PhysicalQuantities::CAngle> *>(this)->compare(other);
-            }
-
             /*!
              * Register metadata
              */
diff --git a/src/blackmisc/mathmatrixbase.cpp b/src/blackmisc/mathmatrixbase.cpp
index 1ecfb4579..676500bb2 100644
--- a/src/blackmisc/mathmatrixbase.cpp
+++ b/src/blackmisc/mathmatrixbase.cpp
@@ -138,6 +138,42 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        template <class ImplMatrix, int Rows, int Columns> int CMatrixBase<ImplMatrix, Rows, Columns>::getMetaTypeId() const
+        {
+            return qMetaTypeId<ImplMatrix>();
+        }
+
+        /*
+         * is a
+         */
+        template <class ImplMatrix, int Rows, int Columns> bool CMatrixBase<ImplMatrix, Rows, Columns>::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<ImplMatrix>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        template <class ImplMatrix, int Rows, int Columns> int CMatrixBase<ImplMatrix, Rows, Columns>::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CMatrixBase &>(otherBase);
+
+            for (int r = 0; r < Rows; ++r)
+            {
+                for (int c = 0; c < Columns; ++c)
+                {
+                    if (this->m_matrix(r, c) < other.m_matrix(r, c)) { return -1; }
+                    if (this->m_matrix(r, c) > other.m_matrix(r, c)) { return 1; }
+                }
+            }
+            return 0;
+        }
+
         /*
          * Hash
          */
diff --git a/src/blackmisc/mathmatrixbase.h b/src/blackmisc/mathmatrixbase.h
index c373def3b..d06ad3c30 100644
--- a/src/blackmisc/mathmatrixbase.h
+++ b/src/blackmisc/mathmatrixbase.h
@@ -51,6 +51,21 @@ namespace BlackMisc
              */
             QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus
              * \param argument
diff --git a/src/blackmisc/mathvector3dbase.cpp b/src/blackmisc/mathvector3dbase.cpp
index 6eb34e284..133eb3b66 100644
--- a/src/blackmisc/mathvector3dbase.cpp
+++ b/src/blackmisc/mathvector3dbase.cpp
@@ -8,6 +8,7 @@
 #include "blackmisc/coordinateecef.h"
 #include "blackmisc/coordinatened.h"
 #include "blackmisc/blackmiscfreefunctions.h"
+#include <tuple>
 
 namespace BlackMisc
 {
@@ -26,6 +27,39 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        template <class ImplVector> int CVector3DBase<ImplVector>::getMetaTypeId() const
+        {
+            return qMetaTypeId<ImplVector>();
+        }
+
+        /*
+         * is a
+         */
+        template <class ImplVector> bool CVector3DBase<ImplVector>::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<ImplVector>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        template <class ImplVector> int CVector3DBase<ImplVector>::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CVector3DBase &>(otherBase);
+
+            const auto lhs = std::tie(this->m_i, this->m_j, this->m_k);
+            const auto rhs = std::tie(other.m_i, other.m_j, other.m_k);
+
+            if (lhs < rhs) { return -1; }
+            if (lhs > rhs) { return 1; }
+            return 0;
+        }
+
         /*
          * Vector to zero
          */
diff --git a/src/blackmisc/mathvector3dbase.h b/src/blackmisc/mathvector3dbase.h
index 76efe48ff..2d65ebe15 100644
--- a/src/blackmisc/mathvector3dbase.h
+++ b/src/blackmisc/mathvector3dbase.h
@@ -80,6 +80,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Unmarshall from Dbus
              * \param argument
diff --git a/src/blackmisc/nwserver.cpp b/src/blackmisc/nwserver.cpp
index 0095d0ae5..195d54837 100644
--- a/src/blackmisc/nwserver.cpp
+++ b/src/blackmisc/nwserver.cpp
@@ -1,5 +1,6 @@
 #include "nwserver.h"
 #include "blackmisc/blackmiscfreefunctions.h"
+#include <tuple>
 
 namespace BlackMisc
 {
@@ -18,6 +19,39 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CServer::getMetaTypeId() const
+        {
+            return qMetaTypeId<CServer>();
+        }
+
+        /*
+         * is a
+         */
+        bool CServer::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CServer>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CServer::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CServer &>(otherBase);
+
+            const auto lhs = std::tie(this->m_name, this->m_description, this->m_address, this->m_port);
+            const auto rhs = std::tie(other.m_name, other.m_description, other.m_address, other.m_port);
+
+            if (lhs < rhs) { return -1; }
+            if (lhs > rhs) { return 1; }
+            return compare(this->m_user, other.m_user);
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/nwserver.h b/src/blackmisc/nwserver.h
index 7e95b3a2d..9e47ec84c 100644
--- a/src/blackmisc/nwserver.h
+++ b/src/blackmisc/nwserver.h
@@ -181,6 +181,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/nwtextmessage.cpp b/src/blackmisc/nwtextmessage.cpp
index 9ac6867c7..a6786ed02 100644
--- a/src/blackmisc/nwtextmessage.cpp
+++ b/src/blackmisc/nwtextmessage.cpp
@@ -28,6 +28,34 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CTextMessage::getMetaTypeId() const
+        {
+            return qMetaTypeId<CTextMessage>();
+        }
+
+        /*
+         * is a
+         */
+        bool CTextMessage::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CTextMessage>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CTextMessage::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CTextMessage &>(otherBase);
+
+            return this->m_message.compare(other.m_message);
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/nwtextmessage.h b/src/blackmisc/nwtextmessage.h
index b7576ed45..5b9a4bd62 100644
--- a/src/blackmisc/nwtextmessage.h
+++ b/src/blackmisc/nwtextmessage.h
@@ -234,6 +234,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/nwuser.cpp b/src/blackmisc/nwuser.cpp
index 43c82221c..69e9aa41b 100644
--- a/src/blackmisc/nwuser.cpp
+++ b/src/blackmisc/nwuser.cpp
@@ -1,5 +1,6 @@
 #include "nwuser.h"
 #include "blackmisc/blackmiscfreefunctions.h"
+#include <tuple>
 
 namespace BlackMisc
 {
@@ -19,6 +20,39 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CUser::getMetaTypeId() const
+        {
+            return qMetaTypeId<CUser>();
+        }
+
+        /*
+         * is a
+         */
+        bool CUser::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CUser>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CUser::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CUser &>(otherBase);
+
+            const auto lhs = std::tie(this->m_id, this->m_realname, this->m_email, this->m_password);
+            const auto rhs = std::tie(other.m_id, other.m_realname, other.m_email, other.m_password);
+
+            if (lhs < rhs) { return -1; }
+            if (lhs > rhs) { return 1; }
+            return 0;
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/nwuser.h b/src/blackmisc/nwuser.h
index 20c5de54b..f28af504b 100644
--- a/src/blackmisc/nwuser.h
+++ b/src/blackmisc/nwuser.h
@@ -185,6 +185,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/pqbase.cpp b/src/blackmisc/pqbase.cpp
index cef13d6c9..c9aac01ad 100644
--- a/src/blackmisc/pqbase.cpp
+++ b/src/blackmisc/pqbase.cpp
@@ -74,6 +74,33 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CMeasurementUnit::getMetaTypeId() const
+        {
+            return qMetaTypeId<CMeasurementUnit>();
+        }
+
+        /*
+         * is a
+         */
+        bool CMeasurementUnit::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CMeasurementUnit>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CMeasurementUnit::compareImpl(const CValueObject &/*otherBase*/) const
+        {
+            qFatal("not implemented");
+            return 0;
+        }
+
         /*!
          * \brief Register metadata of unit and quantity
          */
diff --git a/src/blackmisc/pqbase.h b/src/blackmisc/pqbase.h
index 30b7860f7..e5e5a9b99 100644
--- a/src/blackmisc/pqbase.h
+++ b/src/blackmisc/pqbase.h
@@ -230,6 +230,21 @@ namespace BlackMisc
                 return this->getSymbol(i18n);
             }
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus
              * \param argument
diff --git a/src/blackmisc/pqphysicalquantity.cpp b/src/blackmisc/pqphysicalquantity.cpp
index b8f52a4c0..436ad1624 100644
--- a/src/blackmisc/pqphysicalquantity.cpp
+++ b/src/blackmisc/pqphysicalquantity.cpp
@@ -266,22 +266,33 @@ namespace BlackMisc
         }
 
         /*
-         * Compare
+         * metaTypeId
          */
-        template <class MU, class PQ> int CPhysicalQuantity<MU, PQ>::compare(const QVariant &qv) const
+        template <class MU, class PQ> int CPhysicalQuantity<MU, PQ>::getMetaTypeId() const
         {
-            Q_ASSERT(qv.canConvert<PQ>());
-            Q_ASSERT(!qv.isNull() && qv.isValid());
-            return this->compare(qv.value<PQ>());
+            return qMetaTypeId<PQ>();
+        }
+
+        /*
+         * is a
+         */
+        template <class MU, class PQ> bool CPhysicalQuantity<MU, PQ>::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<PQ>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
         }
 
         /*
          * Compare
          */
-        template <class MU, class PQ> int CPhysicalQuantity<MU, PQ>::compare(const PQ &other) const
+        template <class MU, class PQ> int CPhysicalQuantity<MU, PQ>::compareImpl(const CValueObject &otherBase) const
         {
-            if (other == (*this)) return 0;
-            return ((*this) < other) ? -1 : 1;
+            const auto &other = static_cast<const CPhysicalQuantity &>(otherBase);
+
+            if (*this < other) { return -1; }
+            else if (*this > other) { return 1; }
+            else { return 0; }
         }
 
         // see here for the reason of thess forward instantiations
diff --git a/src/blackmisc/pqphysicalquantity.h b/src/blackmisc/pqphysicalquantity.h
index 15fb2cc48..841a6cdaf 100644
--- a/src/blackmisc/pqphysicalquantity.h
+++ b/src/blackmisc/pqphysicalquantity.h
@@ -68,6 +68,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
         public:
             /*!
              * \brief Virtual destructor
@@ -357,16 +372,6 @@ namespace BlackMisc
              * \brief Register metadata of unit and quantity
              */
             static void registerMetadata();
-
-            /*!
-             * \copydoc BlackObject::compare
-             */
-            virtual int compare(const QVariant &qv) const;
-
-            /*!
-             * \copydoc BlackObject::compare
-             */
-            virtual int compare(const PQ &other) const;
         };
 
     } // namespace
diff --git a/src/blackmisc/setnetwork.cpp b/src/blackmisc/setnetwork.cpp
index 92a19a11b..560dd1e54 100644
--- a/src/blackmisc/setnetwork.cpp
+++ b/src/blackmisc/setnetwork.cpp
@@ -34,6 +34,33 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CSettingsNetwork::getMetaTypeId() const
+        {
+            return qMetaTypeId<CSettingsNetwork>();
+        }
+
+        /*
+         * is a
+         */
+        bool CSettingsNetwork::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CSettingsNetwork>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CSettingsNetwork::compareImpl(const CValueObject &/*otherBase*/) const
+        {
+            qFatal("not implemented");
+            return 0;
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/setnetwork.h b/src/blackmisc/setnetwork.h
index b7af81f2e..4a9bb0775 100644
--- a/src/blackmisc/setnetwork.h
+++ b/src/blackmisc/setnetwork.h
@@ -132,6 +132,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/statusmessage.cpp b/src/blackmisc/statusmessage.cpp
index 9160dae63..9501d1ba7 100644
--- a/src/blackmisc/statusmessage.cpp
+++ b/src/blackmisc/statusmessage.cpp
@@ -33,6 +33,36 @@ namespace BlackMisc
         return s;
     }
 
+    /*
+     * metaTypeId
+     */
+    int CStatusMessage::getMetaTypeId() const
+    {
+        return qMetaTypeId<CStatusMessage>();
+    }
+
+    /*
+     * is a
+     */
+    bool CStatusMessage::isA(int metaTypeId) const
+    {
+        if (metaTypeId == qMetaTypeId<CStatusMessage>()) { return true; }
+
+        return this->CValueObject::isA(metaTypeId);
+    }
+
+    /*
+     * Compare
+     */
+    int CStatusMessage::compareImpl(const CValueObject &otherBase) const
+    {
+        const auto &other = static_cast<const CStatusMessage &>(otherBase);
+
+        if (this->m_type < other.m_type) { return -1; }
+        if (this->m_type > other.m_type) { return 1; }
+        return this->m_message.compare(other.m_message);
+    }
+
     /*
      * Metadata
      */
diff --git a/src/blackmisc/statusmessage.h b/src/blackmisc/statusmessage.h
index d7fced67b..3b8054712 100644
--- a/src/blackmisc/statusmessage.h
+++ b/src/blackmisc/statusmessage.h
@@ -147,6 +147,21 @@ namespace BlackMisc
          * \return
          */
         virtual QString convertToQString(bool i18n = false) const;
+
+        /*!
+         * \copydoc CValueObject::getMetaTypeId
+         */
+        virtual int getMetaTypeId() const;
+
+        /*!
+         * \copydoc CValueObject::isA
+         */
+        virtual bool isA(int metaTypeId) const;
+
+        /*!
+         * \copydoc CValueObject::compareImpl
+         */
+        virtual int compareImpl(const CValueObject &other) const;
     };
 
 }
diff --git a/src/blackmisc/valuemap.cpp b/src/blackmisc/valuemap.cpp
index 865c7122d..02bfd12cb 100644
--- a/src/blackmisc/valuemap.cpp
+++ b/src/blackmisc/valuemap.cpp
@@ -38,6 +38,33 @@ namespace BlackMisc
         return s;
     }
 
+    /*
+     * metaTypeId
+     */
+    int CValueMap::getMetaTypeId() const
+    {
+        return qMetaTypeId<CValueMap>();
+    }
+
+    /*
+     * is a
+     */
+    bool CValueMap::isA(int metaTypeId) const
+    {
+        if (metaTypeId == qMetaTypeId<CValueMap>()) { return true; }
+
+        return this->CValueObject::isA(metaTypeId);
+    }
+
+    /*
+     * Compare
+     */
+    int CValueMap::compareImpl(const CValueObject &/*otherBase*/) const
+    {
+        qFatal("not implemented");
+        return 0;
+    }
+
     /*
      * Marshall to DBus
      */
diff --git a/src/blackmisc/valuemap.h b/src/blackmisc/valuemap.h
index be08dbf29..02f9a19f9 100644
--- a/src/blackmisc/valuemap.h
+++ b/src/blackmisc/valuemap.h
@@ -131,6 +131,21 @@ namespace BlackMisc
          */
         virtual QString convertToQString(bool i18n = false) const;
 
+        /*!
+         * \copydoc CValueObject::getMetaTypeId
+         */
+        virtual int getMetaTypeId() const;
+
+        /*!
+         * \copydoc CValueObject::isA
+         */
+        virtual bool isA(int metaTypeId) const;
+
+        /*!
+         * \copydoc CValueObject::compareImpl
+         */
+        virtual int compareImpl(const CValueObject &other) const;
+
         /*!
          * \brief Stream to DBus <<
          * \param argument
diff --git a/src/blackmisc/valueobject.cpp b/src/blackmisc/valueobject.cpp
index 0fd03beb2..47a4b2a36 100644
--- a/src/blackmisc/valueobject.cpp
+++ b/src/blackmisc/valueobject.cpp
@@ -87,11 +87,21 @@ namespace BlackMisc
     /*
      * Compare
      */
-    int CValueObject::compare(const QVariant & /** qv **/) const
+    int compare(const CValueObject &v1, const CValueObject &v2)
     {
-        // not all classes have to implement this
-        qFatal("Property by index as string not implemented");
-        return -1; // avoid compiler warning
+        if (v1.isA(v2.getMetaTypeId()))
+        {
+            return v2.compareImpl(v1) * -1;
+        }
+        else if (v2.isA(v1.getMetaTypeId()))
+        {
+            return v1.compareImpl(v2);
+        }
+        else
+        {
+            Q_ASSERT_X(false, Q_FUNC_INFO, "Attempt to compare between instances of unrelated classes");
+            return 0;
+        }
     }
 
     /*!
diff --git a/src/blackmisc/valueobject.h b/src/blackmisc/valueobject.h
index d38072bbd..e011272fc 100644
--- a/src/blackmisc/valueobject.h
+++ b/src/blackmisc/valueobject.h
@@ -141,6 +141,15 @@ namespace BlackMisc
          */
         friend bool operator!=(const CValueObject &uc, const CValueMap &valueMap);
 
+        /*!
+         * Compares two instances of related classes
+         * and returns an integer less than, equal to, or greater than zero
+         * if v1 is less than, equal to, or greater than v2.
+         * \return
+         * \pre The runtime types of the two objects must be the same or related by inheritance.
+         */
+        friend int compare(const CValueObject &v1, const CValueObject &v2);
+
     public:
         /*!
          * \brief Virtual destructor
@@ -179,15 +188,6 @@ namespace BlackMisc
          */
         virtual uint getValueHash() const = 0;
 
-        /*!
-         * Compares with QVariant with this object
-         * and returns an integer less than, equal to, or greater than zero
-         * if this is less than, equal to, or greater than QVariant.
-         * \remarks allows sorting among QVariants, not all classes implement this
-         * \return
-         */
-        virtual int compare(const QVariant &qv) const;
-
         /*!
          * \brief Virtual method to return QVariant, used with DBUS QVariant lists
          * \return
@@ -257,6 +257,30 @@ namespace BlackMisc
          */
         virtual QString convertToQString(bool i18n = false) const = 0;
 
+        /*!
+         * \brief Returns the Qt meta type ID of this object.
+         * \return
+         */
+        virtual int getMetaTypeId() const = 0;
+
+        /*!
+         * \brief Returns true if this object is an instance of the class with the given meta type ID,
+         *        or one of its subclasses.
+         * \param metaTypeId
+         * \return
+         */
+        virtual bool isA(int metaTypeId) const { Q_UNUSED(metaTypeId); return false; }
+
+        /*!
+         * \brief Compare this value with another value of the same type
+         * \param other
+         * \return Less than, equal to, or greater than zero if this is
+         *         less than, equal to, or greather than other.
+         * \pre Other must have the same runtime type as the this object.
+         * \remark It is usually safer to use the friend function compare() instead.
+         */
+        virtual int compareImpl(const CValueObject &other) const = 0;
+
         /*!
          * \brief Marshall to DBus
          * \param argument
diff --git a/src/blackmisc/vaudiodevice.cpp b/src/blackmisc/vaudiodevice.cpp
index 7208d5c36..4bbd1411e 100644
--- a/src/blackmisc/vaudiodevice.cpp
+++ b/src/blackmisc/vaudiodevice.cpp
@@ -10,6 +10,7 @@
 #include "vaudiodevice.h"
 #include "blackmisc/blackmiscfreefunctions.h"
 #include <QtNetwork/QHostInfo>
+#include <tuple>
 
 namespace BlackMisc
 {
@@ -90,6 +91,39 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CAudioDevice::getMetaTypeId() const
+        {
+            return qMetaTypeId<CAudioDevice>();
+        }
+
+        /*
+         * is a
+         */
+        bool CAudioDevice::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CAudioDevice>()) { return true; }
+
+            return this->CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CAudioDevice::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CAudioDevice &>(otherBase);
+
+            const auto lhs = std::tie(this->m_type, this->m_deviceIndex, this->m_deviceName, this->m_hostName);
+            const auto rhs = std::tie(other.m_type, other.m_deviceIndex, other.m_deviceName, other.m_hostName);
+
+            if (lhs < rhs) { return -1; }
+            if (lhs > rhs) { return 1; }
+            return 0;
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/vaudiodevice.h b/src/blackmisc/vaudiodevice.h
index 159518f20..4b1fca4e7 100644
--- a/src/blackmisc/vaudiodevice.h
+++ b/src/blackmisc/vaudiodevice.h
@@ -126,6 +126,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/src/blackmisc/vvoiceroom.cpp b/src/blackmisc/vvoiceroom.cpp
index 9cd73d191..4773b0cea 100644
--- a/src/blackmisc/vvoiceroom.cpp
+++ b/src/blackmisc/vvoiceroom.cpp
@@ -9,9 +9,9 @@
 
 #include "vvoiceroom.h"
 #include "blackmisc/blackmiscfreefunctions.h"
-
 #include <QChar>
 #include <QStringList>
+#include <tuple>
 
 namespace BlackMisc
 {
@@ -85,6 +85,39 @@ namespace BlackMisc
             return s;
         }
 
+        /*
+         * metaTypeId
+         */
+        int CVoiceRoom::getMetaTypeId() const
+        {
+            return qMetaTypeId<CVoiceRoom>();
+        }
+
+        /*
+         * is a
+         */
+        bool CVoiceRoom::isA(int metaTypeId) const
+        {
+            if (metaTypeId == qMetaTypeId<CVoiceRoom>()) { return true; }
+
+            return CValueObject::isA(metaTypeId);
+        }
+
+        /*
+         * Compare
+         */
+        int CVoiceRoom::compareImpl(const CValueObject &otherBase) const
+        {
+            const auto &other = static_cast<const CVoiceRoom &>(otherBase);
+
+            const auto lhs = std::tie(m_hostname, m_channel, m_connected, m_audioPlaying);
+            const auto rhs = std::tie(other.m_hostname, other.m_channel, other.m_connected, other.m_audioPlaying);
+
+            if (lhs < rhs) { return -1; }
+            if (lhs > rhs) { return 1; }
+            return 0;
+        }
+
         /*
          * Marshall to DBus
          */
diff --git a/src/blackmisc/vvoiceroom.h b/src/blackmisc/vvoiceroom.h
index 5bd5d32d8..acd57dcb6 100644
--- a/src/blackmisc/vvoiceroom.h
+++ b/src/blackmisc/vvoiceroom.h
@@ -166,6 +166,21 @@ namespace BlackMisc
              */
             virtual QString convertToQString(bool i18n = false) const;
 
+            /*!
+             * \copydoc CValueObject::getMetaTypeId
+             */
+            virtual int getMetaTypeId() const;
+
+            /*!
+             * \copydoc CValueObject::isA
+             */
+            virtual bool isA(int metaTypeId) const;
+
+            /*!
+             * \copydoc CValueObject::compareImpl
+             */
+            virtual int compareImpl(const CValueObject &other) const;
+
             /*!
              * \brief Stream to DBus <<
              * \param argument
diff --git a/tests/blackmisc/testvariantandmap.cpp b/tests/blackmisc/testvariantandmap.cpp
index 44e49c6c5..a9a145d18 100644
--- a/tests/blackmisc/testvariantandmap.cpp
+++ b/tests/blackmisc/testvariantandmap.cpp
@@ -46,6 +46,10 @@ namespace BlackMiscTest
         QVERIFY2(station1 == station1qv, "Station should be equal (QVariant)");
         QVERIFY2(station2 == station1qv, "Station should be equal (QVariant)");
         QVERIFY2(station3 != station1qv, "Station should be equal (QVariant)");
+
+        QVERIFY2(compare(station1, station1) == 0, "Station should be equal");
+        QVERIFY2(compare(station1, station2) == 0, "Station should be equal");
+        QVERIFY2(compare(station1, station3) != 0, "Station should not be equal");
     }
 
     /*