I've been using Fedora with KDE as my primary system for a year now. And after switching from f14 to f16 2 months ago I decided to leave KDE and try the gnome3 again (perhaps Unity on ubuntu). Why? Because KDE sucks. Ok, I should explain. KDE is great. So much better than gnome2 that people love for some very strange reason (but I guess some /same?:)/ people loved win95). I love its customizability. I like its unified feel across the apps. But out of the box feel is really bad. It looks bad, it works bad. I would say it's Fedora's problem as the KDE really is capable.. but still. Also, the apps are painful sometimes. But it's not different from GTK "suite" from what I've tried.

PS: It's my personal opinion of course. Maybe I'll switch back to KDE right after I try the Unity.

My first distro was openSuSE 10.1, before KDE4, in 2006. The system has been upgraded to a new machine, now headless, and now lives on openSuSE factory. Running through VNC KDE is still a decent interaction. It spoiled me to all other implementations of KDE. OpenSuSE has a lot of other tidbits going for it too. YAST2 being huge!