Proton is a very impressive project and works with many titles that I've tried. For anyone not well acquainted with it and wanting to try games not part of Steams official compatibility list, look at https://www.protondb.com/, think of it as similar to Wine DB. For unsupported games, I usually use GloriousEggroll's custom build: https://github.com/GloriousEggroll/proton-ge-custom. This "fixes" many games, especially if they use videos in cutscenes and many other things.

There are some features that I was never able to get working correctly, e.g. remote Steam Play with Streets of Rage 4 where my friends stream would not load up or controllers would not map, but for single player gaming, this would not be an issue.

Performance is (to be expected) less than Windows and games can exhibit graphical artifacts or crashes but it is not bad enough really complain about given how amazing it is that this exists in the first place. I will often put up with these (imo) minor defects than boot to my Windows install. Steam cloud sync even works correctly for keeping your save data between OS'!

One thing to be aware of that I don't see people mention (maybe because it's a niche setup and game dependent), is that using fractional scaling can completely mess up some games display, I believe due to how fractional scaling uses a framebuffer larger than your real resolution. Make sure to set your scaling to 100% before launching games which have this behaviour, e.g. Tekken 7.