For the little glimpses that I've seen, UI development using Qt Quick and QML and is actually pretty nice. Nothing like the Symbian hell, and seemed a good deal more fun than developing for Android. (Can't say it's on par with iOS though, at least not yet.)
This is the first time I'm actually _excited_ by a Nokia technology.
Now is a good time to check it out, since the first phones supporting 4.7 are supposed to come out "soon" (my source at Nokia was reluctant at naming a specific date). And they just put out a new technology preview:
http://labs.qt.nokia.com/2011/01/20/qt-sdk-1-1-technology-pr...
If Qt / QML Quick seems a bit barebones, there's a library called Qt Components which adds things like checkboxes, progress bars etc.: