The combined overview (four-finger swipe up) is one of the main things I felt was missing from Gnome and macOS and is really nice! I wish it was a three-finger swipe, but it's KDE, so you know there's probably an option somewhere.
I'm also excited about being able to consume HDR content on my workstation where I have a much nicer monitor, so will have to report back on that.
I really dislike the new default lock screen wallpaper. Not entirely sure why.
Plasma 6 fixes the panel configuration mess, which was pretty buggy. It works flawlessly now while being more intuitive.
The new Breeze theme fixes a lot of the spacing inconsistencies that irked me here and there. It looks much better now.
Fingerprint unlock had some weird bugs as well, which all seem to be ironed out. Very clean and consistent now.
Even the new default sound theme is _super_ nice. I'm a huge fan of the new sound effects across the desktop environment. Seriously, they're so good.
New screen recording stuff just works (Super+R) and the PipeWire setup plays perfectly with OBS. Can record individual windows and it all seems to work as expected.
Still not entirely sure this will replace Sway for the serious workstation multitasking sessions and the advantages that a tiling window manager brings, but it's really a joy on my laptop.
I know a lot of people (rightfully) have their gripes with Wayland, but this feels pretty feature complete to me. The last missing piece I'm personally feeling is remote desktop access, but I admittedly have not done anything there yet. Since screen capture is working perfectly and KDE Connect to control machines remotely from my phone works, I'm guessing the pipes are all in place and I simply need to set things up.
If you're feeling curious, give it a shot! I think it's a fantastic starting point.