I suppose it really depends on when you tried it. Ubuntu 23.10 has been working quite well on Wayland. I haven’t once failed down to X, and the only papercut I run into now is with differently scaled displays (100% and 150%) where OBS will crash the session when moving back and forth.
Everything else seems good as I haven’t really seen anything else break at all and I use Firefox, Kdenlive, Audacity, lots of chat apps, and played some games. Specifically, playing Vivaldia 2 while I was remotely compiling Gentoo using OBS to livestream.
There really isn’t one. Wayland is maturing and app support is following.
This is the way things always go in open source. I’m betting soon there will be a distro that will announce a never Wayland stance just like Devuan prior.