Both reviews on the apple website and pretty bad (2/5 stars), and they either talk about bugs and that the controls are clunky. Mind you there are only 2 reviews.
I can't say anything about the bugs, but the controls are the exact same as on a PC. Games like GTA have always been a bit awkward to play with mouse and keyboard, while much easier to play with a gamepad using, for example, a PS2 or XBOX. It is something to get used to, and not something to bash the game for, just because there are no good gamepads out for the Mac.
I got the Mac version for christmas.
I formerly had the windows version installed in a small win7 partition. I use a real PS2 controller with a USB adapter. Works great.
Back to the Mac version. 2 days later, I still have yet to get any game in the set to run on any of my Macs. First it was random OpenGL errors, then it was the secret hidden activation key. Now that I've found that, none of the games will run because they claim they can't find my Mac Pro's CD/DVD drive. What the **** does it need to see my drive for anyway? But it can't, and won't run because of it. The error window has a link for more information. The page it links to, is for Windows. Rockstar hasn't put any effort into a game since 2004. I'm going to return this crap, total waste of time and money.