Qt was a good concept, QML sort of ruined it for me, the way Maemo 5 had Qt was the best way, have stock QWidgets themed with a theme engine so it looks similar to the OS.

Harmattan didn't implement this sadly, so QWidget based apps look/behave bad on it, so you're stuck with rewriting your Qt apps again for Harmattan.
Instead of writing a theme engine for Harmattan, Nokia embraced QML, which is not that mature imo. MTF is good but involves rewriting the app, and it's only compatible with MeeGo then. QML is good but you have to do everything from scratch (components are just examples prepared in a package in my opinion).