Funny you say that, but on a limited Linux VM, it's the only environment that runs and looks relatively decent.
KDE - Looks great, runs like a slug stuck in molasses.
Gnome - Looks meh, runs slightly better.
Unity - Looks great, same performance as KDE.
For whatever reason XFCE gets accused of looking ugly, but I tend to agree with you. It looks fine out of the box, better with some minor tweaking, and is fully themeable if you're into that sort of thing.
KDE always had a reputation for being a bit of a resource hog. Gnome 3 was a rewrite in Javascript, so no surprises there. I never personally used Unity, but it always felt a little annoying when I had to use it on other computers, probably due to the layout and corner gestures.
Re:Xfce 4.16
by stjohnswarts on Wednesday December 23, 2020 @03:46PM
(#25522014)
The latest version of KDE (past year or so) uses approximately the same "freshly launched" size as XFCE does and is as snappy as anything else on a relatively modern system (when compared to Gnome3 and XFCE). I think the main reason to pick XFCE is the interface and overall stability not because it's lighter than KDE any longer.
If you think Windows usability peaked around Windows XP, XFCE might be worth trying.
All I want is an application menu, some launchers, a window list, a widget/notification area, and some reasonable keybindings. Gnome 2 had these things, and then early Gnome 3 got rid of basically all of them. If some fancypants UX researchers want to experiment with replacing menu bars with hamburgers, that's fine, but I'm just not interested.
I've done more than my fair share of WM hopping (I still use i3 on my laptop because I like being able to resize windows with my keyboard when I don't have a mouse), but XFCE is my workhorse. It may look boring, but it's reliable. It has more than enough features for working productively, and I appreciate the fact that the development team doesn't completely change the way everything works every few years just to chase the latest flashy trend.