While I don't own an i-Device, I'm actually looking forward to Mountain Lion. To me it isn't just the big advertised features, but the small-little tweaks. Look at the "All the Little Things Thread". The biggest advertised feature that I am eager to use is Game Center, Steam is more for the hardcore gamer and the games are very expensive. Game Center as I see it, is geared more towards the casual user. I can't wait to be able to play games with friends on iOS devices because I haven't been able to in the past.