New Macs play the game just fine under Snow Leopard, no difference whatsoever between the windows version in bootcamp!

User Rating: 9 | Starcraft II: Wings of Liberty MAC
The game is quite addictive, I wasn't expecting it, but it makes you wanna play more and more. The campaign is really good, as for the multiplayer, well you'll have to have a lot of patience cause there are a lot of good players out there. But practise makes perfect as they say.
If you haven't played the game yet, get a guest license and go for it. You'll see that even if you are not a fan of strategy games, (which believe me, I wasn't), you'll be one in the near future.
I've installed it on my macbook pro and I didn't have any problems. So new iMacs, Macbook Pro's unibodies won't have a problem at all. Good FPS and no difference at all when I've installed it under Windows 7 on the bootcamp partition. So if you don't want to dual boot every time you want to play that game, you don't have to.
Enjoy the game under your Mac OSX.