Xfce was my long-term desktop until recently. I loved that it was lightweight, clean, and generally well thought-out.

It has become more memory-hungry since then, losing some of its early advantage. And with the move to Gtk 3, it has adopted UI patterns that constantly get in my way. (Client-side window decorations, for example.) I worked around those changes as best I could for several minor versions, but eventually gave up the fight and switched to KDE. Turns out Plasma slimmed down a bit while Xfce was gaining weight, and it lets me turn off the bells and whistles that I don't want.

I'm happy to once again have a desktop that I enjoy using. I do miss Xfce's Thunar, but KDE's Dolphin is mostly not bad.