I've been using Xfce on everything since about 2010. It's my default on my Ubuntu and OpenBSD VMs/workstations.

Xfce promotes a good deal of minimalist motifs, which is nice. I found Gnome 2 and Unity quickly excessive with clutter.

I've been on XFCE on Debian since KDE 4 came out. Recently I had a fresh install and checked gnome out of curiosity and it turns out I'm too old-fashioned for this.

KDE4 came out a long time ago, back then 4.0 was derided as a beta-quality clusterfuck but it's come a long way.

This past weekend I installed KDE 4.10 on a FreeBSD 9.2 vm using the new "pkgng" tools. Completely painless. KDE 4.10 is very polished.

Gnome 3 is awful IMO. It's not NEARLY as bad as Unity, but I still prefer Xfce myself too.

I thought Gnome 3 had some potential, especially if I could hook shortcuts up to replace all the clicking. It seemed to be imitating OS X, which felt like a good thing[1].

However, I don't have time to figure out how to "fix" it for my personal needs, and I can't be bothered if it involves more than a single conf file I can save in a gist...and it's certainly not compelling enough to move me back from something as simple as XFCE.

[1] note: I don't use most features in OS X, but the dock and whatever "show me all the desktops" is called, I do heavily, as well as a keystroke launcher.