I tried it out for a while and I think a new feature? is that you can control de brightness of the monitor through Plasma. Cool for one monitor but I have 2 and one is brighter than the other at a given brightness %, so it got a bit annoying. I didn't look further into it but when 6.1 is released on Fedora I will probably need to.
Additionally the SDR colors when HDR is turned on looked better overall. Better than Windows was able to do even. Awesome stuff
I tried the beta out for a week, and overall it was fine. One super annoying thing I can into I couldnt figure out though was paste was borked. I could copy text, see it in the clipboard cache, but when trying to paste, the window I would try to paste into (several apps) would freeze for 30 seconds or so, and then not paste. Very odd.