It works pretty well. I don't currently play any pc games with anti-cheat, so most games work well without having to do anything special outside of running them in Wine or some other application and there are some games that actually work noticeably better on Linux than Windows. Some games have required some additional setup but it's pretty rare for games to just not work at all. Something I find kind of funny though, is that most of the games I haven't been able to get working on Linux aren't working on Windows either.

I should also mention that I don't really use mods for games. I have used mods for the Linux version of SRB2 but the game is designed to be easily modable, so it makes sense that the mods would just work.