If you have not tried QML yet: I used to love Qt because it was soo easy, then loved PyQt because it was soo much easier. Now I love QML because it is soo much easier still. QML really is an awesome way of creating GUIs and interaction logic. Then code your backend in whatever language you like. PyQt works just as well as C++, and since you don't have to wrap GUI logic at that point, the language doesn't matter as much.
As for Python that's not what you want to use with QML and pure Qt is not what you want to use for mobile apps.
It includes a domain specific language for creating widget trees called kivy language, which I hear is not unlike qml (though I haven't tried the latter), though it all maps straight to pure python if you want to write things that way.