I'm the "debian-stable" kind of user, So i was until recently under KDE 3.X, and very satisfied. I has seen KDE 4.x running, and wasn't that convinced...
Then, debian squeeze went stable, I just followed the way. OMG, what did they do to my box ??? It's just so slow now !!
Coincidentally, I upgraded my computer. OK, brand new machine, let's see how KDE 4 is doing now... Then again, I couldn't find my marks.
OK, let's give a try to gnome (2.30.3 with squeeze).
Well, after a bit of tuning, I'm quite satisfied with its usability.
Nethertheless, I'm still using of few KDE Applications, for which I didn't find a good replacement on gnome (Konsole, Akregator, Kdiff3, Klipper...).
Use to be a KDE Fanboy, i'm not anymore...