Speaking of the refresh rate, I thought this was a nice change (pulled from a TomsHardware review):

With the new 90 Hz refresh rate, Valve has made one significant change to the Performance menu in SteamOS. It has combined the refresh rate and fps limit into one bar: “game refresh rate,” which Valve says will add more options, like “frame tripling a 30 FPS limited title on the 90Hz refresh rate screen.”