I have no intention of starting a DE war here (I hate these wars anyway) but I will say my opinion as detailed as possible. It's up to the reader to decide for themselves. Remember that this is my personal opinion and it will never change, I'm not obligating anyone to agree with me.
My favorite desktop which I'm using 9th year in a row is Cinnamon (which is a fork of Gnome 2, I think) but I use separate apps from KDE and Gnome. Cuz from both DEs some apps are very good and cool (like kolourpaint, gedit, pluma, whereas these two whole desktops are simply not my thing. But ever since GTK4 came officially and Gnome started migrating everything to GTK4, I had to start downgrading and freezing those apps at GTK3 versions because GTK4 is horrible - nothing to do with GTK3, no dark themes either, thus they all appear white. Even the CSS files of GTK4 are too different from GTK3, so I can't even begin to understand which file(s) I should edit in order to have the GTK3 look in GTK4.
The Linux Mint team (the developers of Cinnamon) started gnomifying Cinnamon slowly but surely (that process began with removing support for metacity in Cinnamon 5.4.0, so no more flipping and V-Sync in native linux games (no flipping means V-Sync doesn't work and quite often you can see what appears to be an FPS drop, despite that mangohud may still show stable 60 FPS). I have reported that problem twice but they seem to be not inclined to fix it, so it's a matter of time before I say "Farewell, Cinnamon). And by removing metacity they also removed the option to choose a custom window decoration, so now (just like on Gnome) all of your windows have the same window decoration (or title bar, if you will) and you can't change it in any way.
I'll keep using Cinnamon 6.x for as long as I can. When the gnomification changes become too many, I'll most probably move to Plasma 6 because that's the only desktop as close as possible to Cinnamon and my needs, despite that it has thousands of options that I don't need and never will and some are even ridiculous.
The rest of the desktops are just way too cut off regarding functions and customization options. For instance, on MATE you can't make the panel to be 100% transparent or semi-transparent because when you do that, all the apps that were added to the panel disappear along with the panel's color and if you make it 100% transparent, the same thing happens with the apps icons added to the panel.
The last time I tried XFCE it was still using GTK2 which didn't support transparency, so my only chose for the panel and a few other things was a solid color because GTK2 supported only HEX code colors. Luxuries like RGBA format was just a dream in XFCE. IDK if they have migrated to GTK3 yet.
LXQt, LXDE are even worse than MATE & XFCE, I won't even start listing the problems with the other less popular desktops, so that leaves me with one choice only - migrating to Plasma 6 some day, hopefully not too soon.
en.wikipedia.org
