My biggest issue with QT is that there aren't really any bindings for different languages. I'm not a big fan of GTK but it's nice that most popular languages have bindings in it. I was able to get pretty far with the C# gtk bindings, but the app ended up being a little too slow for me and I couldn't find any good answers for it on the gnome forums. I'm now using AvaloniaUI but woo boy is that learning curve steep. I can see the benefits of Model View ViewModel, but it takes a bit to wrap your head around.<p>Unfortunately the most successful people I've seen use AvaloniaUI have all been Ex WPF developers, and having gone through some WPF tutorials I can see why.