@DCMonkey: Developing for Symbian has always been a pain. And the people who like Qt are (in my point of view) mostly comming from C or C++ and love the fact Qt gives you so much more power.
I think the WP7 platform will open up there eyes. The tools stay free, the apps look better and can be developped faster. It does have it's painpoints but I'm sure Microsoft will address them.
I've worked on a Qt application for the N900 and it was not unpleasent. But the tools still don't compair to Visual Studio. They were great and very visual, and brought some good stuff to the table. But nothing compaires to Visual Studio.
Also, Qt had just released a language based on JSON to discribe layout elements. Much like XAML discribes the layout in WP7 apps. So if they choose to transition to the bigger ecosystem they should be in for a treat.