Have you subclassed any GObjects lately? Or otherwise implemented custom GTK widgets? If so, you might know why GTKmm exists (nevermind that PyGTK, GTK# etc are arguably the intended ways to use GTK.) There is a good reason everyone in the Linux world screamed with glee when Nokia LGPLed Qt, and C++ (even the basic stuff) is a big part of that reason.
I'll second that. Qt is a beautiful toolkit. It's just enough C++ to be useful, and avoids all the templates and obnoxious flotsam that makes that language such a horror. Signals and slots work great, and other tools (qmake for example) are a pleasure to use.
