KDE I have no explicit love for either, mind you. It's cluttered and has too much inter-dependence on it's apps and libraries. E.g. if I want to install Konversation, I have to install half of KDE with it. Not to mention that ugly-ass default theme, ugh.
XFCE uses GTK2, and is suuuuuuper ugly by default. Openbox/Fluxbox are beyond too simple for my personal needs.
Cinnamon is what I wish GNOME 3 would have been.
At the moment I'm using XFCE with a heavily customized theme only because XFCE is the default on my current distro (Manjaro). But I distro-hop a lot so that may change soon.
NOTE HOWEVER that I am immensely proud of the GNOME team for pushing Wayland support so far so fast. It just goes to show that they have a great team of developers who can write great code.
They just have a horrible team of designers who push the developers to create interfaces that look like crap. GNOME 3 to me seems like it's saying, "Fuck the desktop, nobody uses THAT anymore! It's all MOBILE now!! Who needs notification icons that change color instead of sending you 100 notifications per second for messages in an IRC channel. We'll just HIDE ALL NOTIFICATION ICONS like the worthless shit it is."
Love ya GNOME devs
Hate ya GNOME designers