I have a feeling gnome has struggled more with wayland than kde. For a while i could not drag and drop across screens or to applications i switched to with alt+tab. I dont know if those are fixed. One that isn't fixed that I had happen just yesterday: menus locking focus to one app. If I open the file transfer popup in nautilus I have to first close by clicking somewhere else in nautilus, or else I can't click anywhere. I don't think I ever had that issue under x.
The only bugs I have seen in KDE are in sddm, but I managed to find a theme where they don't exhibit.
I am holding on to xorg until i can shade Windows and use something with half the power of xinput to configure my trackball. Oh, and I also want to be able to have many different keyboard layouts for sddm. Most themes fail to display a layout selection menu that isn't blank for me.
Otherwise I don't really mind wayland.