I’m definitely a bit biased against gnome so keep that in mind, but that’s because I have really really not enjoyed using it when I do. I even keep trying to use it on occasion as I keep it installed on my computer and give it another try on occasion to see how it evolves. But in short, I really really dislike gnome, all the way up to version 3 is what I’ve tried, we’ll see how 4 goes but based on this article I’m not going to be a fan of it either.
KDE on the other hand, I’m an absolute fan of. Not only is it incredibly lightweight (even lighter than most “lightweight” DE’s), but it’s “Activities” (not to be confused with gnome activities, which is basically just the running/runnable programs) are basically the multi-desktop view well known on X but to a significantly enhanced degree, and it’s amazing to add to your workflow. In addition, the sheer customizability of KDE and it’s ability to change to adapt to anything from huge Desktop views to phone interfaces is unmatched in my opinion thus far.
A fun thing to note, KDE by default is…fairly windows styled, but you can make it look like a mac, like gnome3, like gnome2, like gnome4, like unity, like basically anything else you could near imagine (short of VR interfaces, though that’s being worked on as well by others). It’s configurability is unparalleled by any other DE.