Thanks for the youtube links, Proton looks awesome, solid improvements over what Phoronix had in their reviews. Still, we're looking at 80-90% performance of Windows 10 which isn't parity. Anything with an interpretation/translation layer is going to have an overhead penalty.
I can't find any written article roundups since August 21 since latest version has only been out for a month. Also it has a limited compatibility list:
https://steamcommunity.com/games/221410/announcements/detail/1696055855739350561. That being said, very cool that Valve is pushing this forward.
Doesn't change the fundamental analysis that buying Windows 10 on a dollar-per-FPS basis is the best upgrade once you're in midrange cards or above.