To each their own.
Until GNOME, xfce, and the other "desktop environments" come up with something akin to KIO slaves, I'll be sticking with KDE. That, and the sheer amount of code re-use due to KParts and kdelibs, are what keep me with KDE, as it leads to much nicer integration among apps and much better conformity among apps. Not to mention the sheer configurability of the environment ... I've tried to get GNOME and xfce setup to look and work the way I want, and it just doesn't work for me. Neither at home, nor at work.
But, the beauty of Unix-like systems, is that everyone can find the environment (or even just WM) that works for them, that suits the way they work, and can use it.
Love live choice!
Oh, and I have KDE 4.1.0 compiling on my home workstation as I type.