Valve fixed one of my big issues with Steam Machines... kinda. Games with their own launchers (e.g. Trine 3, Starbound, and Evoland) won’t, well, launch. Valve has removed the SteamOS-compatible tag from around 35 games. Some devs are working on new launchers. Fingers crossed that everything’s resolved by release day.
Rocket League is coming to SteamOS, and it’s free if you buy a Steam Machine, Steam Link, or Steam Controller. The car soccer sensation is great fun in split screen, so the pairing makes perfect sense. Also, it’s sold one million copies on Steam alone. I get the impression that maybe people like it a little.