I've got a 2009 MBP 13" with the 9400M, 8GB RAM, and a 256GB SSD.
Starcraft 2 under default settings on the Mac isn't anything to write home about. It's a bit slow, clicking on units isn't as fast as I'd expect. Sometimes in combat I'd have to click on a unit several times for the click to go through. Things will slow down significantly during battles, a few skipped frames.
Overall I'm very disappointed that this 9 month old MacBook Pro, the darling of its line, souped out with a solid state drive and 8GB of RAM, still cannot play Starcraft 2. What's shocking also, although in a sense encouraging, is that I can dual boot it into Windows and it will play just fine.
Why have nVidia, Apple, and Blizzard (or some subset of the three) forsaken us? Why do I need to boot into Windows to play Starcraft 2?
Is there any solution coming? Is it a problem with OS X? The graphics drivers? Starcraft 2 itself? Who will fix this?
I'd really prefer to NOT have to boot into Windows, but I suppose if I have no other choice, I should start looking into the option. I'm amazed that none of those companies have acknowledged the performance issues and voiced their plans to fix them.