I'm curious if the Mac version of Starcraft II will perform approximately as well as the PC version on Bootcamp or if there will be any stability/performance compromises. Is SCII a native port on Mac or is it wrapped? Also, are the tech support teams separate (ie can we expect simultaneous and synchronized updates and bugs)?
The biggest issue that I am aware of for Mac Starcraft 2 is that 10.6.4 makes the game very unstable if you have an nVidia graphics card. It crashed just often enough for me to get annoyed by it, so I re-installed my OS and only updated to 10.6.3. Things are much better now (this is likely the same issue as Steam has on 10.6.4, and probably requires a patch by Apple to fix - I'm not positive on this, though).
I'm not sure of the technical details of Starcraft 2 on the Mac, but I think that it is a native client. All of Blizzard's games (at least dating back to Diablo, maybe earlier) are released on Windows and Mac, so most likely they have a good build process for building their games cross platform.