I've switched to kde-unstable as soon as it was updated, and am quite happy to say, it's been really damn solid. The only issue I've experienced was that Firefox somehow does not support explicit sync, and crashes the parent process of the broken tab near instantly
Sadly not so much for me. Minimize/maximize animation stutters, mouse stutters if explicit sync is enabled (unrelated to min/maximizing, had to disable it), some windows dont maximize to the right size and hovering taskbar overlaps.
I'll have to look into it and maybe open bugs. Only used 6.1beta for a few hours so far