If you want KDE > opensuse
If you want gnome > ubuntu

Yes, you can install KDE on ubuntu, but it's still very bugged.
If you love debian package system then stay away from opensuse. Even though their KDE is super stable, I couldn't stand the package system that they have. So, I switched back to ubuntu with gnome.

Debian, imho, is not a good choice for desktop, but it's excellent for server.