It runs really good, but this is not a Mac OS X (the last two characters of Mac are lowercase ;)), it's called a native Windows 7.

And I really hate to boot windows on my Mac, it destroys my workflow completely.

Edit: I would love to see GStudio on my Mac, but not in it's current form! Gamestudio doesn't conform to what you expect on a Mac. It feels wrong in so many cases from a Mac user point of view.