Same or similar? It doesn't matter what they provide because I'd go with ScalaFX(http://www.scalafx.org/) + IntelliJ or Vala|Genie + Vala IDE. Mono is also an option if you're into it.
> but it is stuck in C + POSIX as technology stack in what concerns developer experience.
Yes, GTK isn't the newest but it isn't hard at all to develop apps with Vala/Genie(https://wiki.gnome.org/Projects/Vala/GTKSample , https://wiki.gnome.org/Projects/Genie/GtkGuiTutorial ?)
> Vala is still not there and I don't believe in JavaScript for native UIs.
What do you mean? Vala is almost the defacto standard language for ubuntu/gnome apps.