It's pretty awesome. Some of the compatibility layers built on Wine (Valve's Proton/Codeweavers Crossover/Whisky) are almost plug and play. With Steam on Linux, a lot of games work seamlessly. I've only ran into trouble with very new games and multiplayer games with invasive anti-cheat that freaks out when they're running in an environment that doesn't look like a normal windows install

The performance hit is surprisingly low. It's not rare for the windows binary to run better on linux than the native one (when it's an option)