I have to partly disagree with you about N9. True, it's unfinished and the recent update for PR 1.3 is probably its last. The development environment is not as

I have to partly disagree with you about N9. True, it's unfinished and the recent update for PR 1.3 is probably its last. The development environment is not as mature as iOS, since the Qt SDK didn't have as many years of use. On the other hand Qt and QML are in a completely different league compared to the primitive way of building UIs in Android or iOS. Nokia hit the jackpot with declarative UIs, and then completely failed to build and support a product around them. e.g: Think about iOS - you either code your UI in Objective-C or use a designer. Borland was doing this with its C++ Builder and Delphi lines in 1996. On Android you had to edit XML files by hand for the longest time. WP tooling is the most modern of the three you've mentioned. C# is much nicer that the aged Obj-C and XAML is also a declarative language, but the XML format is bloated and completely uneditable outside of specialized design tools.