I think a lot of the people here believe that *your favorite distro + Steam > SteamOS'. But I'm sure there is nothing wrong talking about it here if you have anything to share, since most people gaming on Linux use Steam.
On that note, I guess I should throw my hat in the ring:
1 - LXLE
2 - Unturned via Steam, Runescape via Unix client, Super TuxKart, 0 A.D.
3- Over a year all Linux no Windows, but still a noob
4 - Ulikebigboom?
On Unturned they recently added a plane and choppers and an Arena mode which is really fun. I hadn't tried it in multiplayer since my internet was terrible until recently. It's amazing how one guy making the whole game is always coming out with updates and adding things people want. Plus it is free to play and $5 for gold membership. I don't play it everyday, but I usually binge on it for hours at a time. Super addictive!
Runescape is, well, Runescape. Now that they have bonds you can buy with in game currency it is a lot better. I never got membership until recently. It's alright. Super TuxKart feeds my Kart addiction better than any of the Mario based games. It works with my Logitech PS2 wheel! 0 A.D. is pretty awesome. Good RTS that really kicks the crap out of my weak hardware when the unit count starts to climb. SNES9X GTK+ is an awesome emulator port for anyone looking to kill time on SNES games. I set it up on my Braswell computer and runs well since nothing else does
I haven't been doing much in the way of gaming besides mostly AFK Runescape and a binge of Unturned here and there. Everything has been running pretty well so I really can't complain. I have a ton of other little physics games that are fun and super cheap on Steam sales. Most of my Steam library is Linux games and some of the others like Airmech and One Way Heroics run well enough in Steam under WINE. There is supposed to be a way to get Airmech to run natively but I never tried it yet. GTA4 barely ran in Windows with integrated graphics and unplayable in Linux, but I haven't tried with newer kernel or graphics stack yet. I'm holding out for *buntu16.04. I need to do more testing with the little graphics card I grabbed a while back. I put my GT 720 in my Braswell computer just for laughs and the whole rig was drawing about 23 watts max. Granted that mobo only has x1 going to the x16 slot and the single core CPU performance was crippling, but I should be able to use it on my HTPC without blowing past the limits of my 90 watt PSU. Just curious if the performance will be much better vs the power increase. I guess there is only one way to find out!