i’m in the same boat. I somehow ended up on KDE (although on Debian, IMHO the distro doesn’t really matter here that much). I had trouble with rotation at first (Tablet mode in KDE? (auto-rotate, virtual keyboard)) but that’s mostly fixed.
(I actually get occasional crashes when rotating, actually. Kwin and sometimes firefox just crash! I still need to report this, not sure what’s up with that..)
Another problem is the status bar at the bottom doesn’t scale very well: sometimes there’s too many icons in the notification area on the right and that squeezes up the window list on the left which becomes unusable. I also miss volume buttons when in tablet mode…
I suspect GNOME would work as well, but I had trouble just getting used to it.
Finally, I am somewhat impressed (or not impressed, I guess) by how poor gesture support is across the board. Simple things like “back and forward” in Firefox, which work on the touchpad (two-finger scroll left goes back!) just don’t work at all on the touchscreen which I find just bizarre. PDF reader support is spotty: the best I’ve found so far is Calibre’s ebook-viewer but I find its UI really bizarre. But it’s the only one that, amazingly, allows for “tap for next page”. All the others either restrict you to tapping a tiny “next” button (GNOME’s, Okular) or have gestures that just don’t work so well (swipe left doesn’t work reliably).
I also find scrolling to be sub-par. On my phone, if i swipe up hard, a webpage will just scroll up and keep scrolling until it slowly decelerates or if i touch it. On this tablet, pages scroll while i swipe up, then immediately stop when i release the touch. This is what you’d expect on a mouse and touchpad, but on a tablet, somehow, I’ve built different expectations.
Those issues are all fixable, but it seems to me there’s a large variety of toolkit-level issues that need to be adressed, it’s not specific to KDE (as, for example, it affects Firefox which is GTK-based, AFAIK)…