I use them every day, so I like to think that I know what I'm talking about. There is no need for the differentiation when working at such a high level. That's the whole point of it, to abstract away the differences in low-level APIs. Of course the low-level code will be different, but the declarative components can, and should, be the same. The bigger problem is that there are many basic features in Symbian that don't work unless you resort to native Symbian C++ code. You can't even use the hardware volume keys in Qt.

Come back when you've tried developing some Qt applications for Meego-Harmattan, Freemantle and Symbian.