KDE on my main gaming PC, or if I want something that looks really modern and sleek without tons of setup/tweaking on another PC.
Mint with Cinnamon if I want a #justworks setup that is rock stable and I don't need to look sexy.
My side business laptop uses LMDE with Cinnamon for that reason. I need that thing to be rock stable and dependable at all times.
Cinnamon has been more stable for me than any other DE, and in my experience, is just as performant as other low-spec favorites like XFCE. My fresh install of LMDE with Cinnamon right after boot uses about 850MB of memory. My testing with XFCE was about the same, maybe 50-75MB less, which for my use case is effectively identical.
Not crapping on XFCE though, I like playing with it on one of my old thinkpads. Not a fan at all of Gnome, I've tried to like it for years, but I just don't care for it, and I experience quite a few bugs.
I plan on trying the new Cosmic DE soon, it seems like Gnome done better, and I could see myself liking it from the reviews I've watched.