I recently purchased a game from them that has been out for over a year, they ran out of CD Keys so Steam gave me the "could not connect to key server" message. After going back and forth with Steam support they refused to issue me a refund or even give me an ETA for when I would be able to play the game that I've already payed for. Horrible customer support and I doubt I'm the first customer they've done this to.
Several weeks later, no game, no refund, no cd key, and no update from their support staff (which is accessible via email only, no chat, no phone). Screw you Valve and Steam, I'll stick to my PC.