The MBA runs SC2 on high settings? My 2.3ghz quad i7 MBP kind of struggles to run it on high (30-40FPS) and it has a 1GB radeon 6750M in it. That's interesting.
I usually play the game on low settings when laddering anyway to reduce any potential lag. I was considering selling that machine and buying a MBA for the increased portability and battery life, but I love playing SC2, so that way my big issue.
It can not run on all high settings very well. I posted earlier in the thread explaining that the front page was not correct (At that time it had said Ultra settings were playable). I suggested at 1440x990 resolution the best is Medium settings with a few scattered high's, like Models, Terrain, and shaders or shadows (I don't remember which one).
When it first boots up on High Settings it gets ~25-30FPS, but quickly drops to ~10-15FPS once some units and action begin, and that is only with light action. It's not playable with a massive army, especially if you need to quickly move units and jump back and forth from your base to your army.