Macs have never been and will never be good machines for gaming. Accordingly, there is no such thing as Mac Gaming. It's always been an illusion, fueled with poorly performing, bad ports of Windows games and promoted by fanboys who don't know any better and have never played on a real gaming rig. The framerates that even the fastest Mac Pro creates are average at best when compared to the graphics power of a middle-sized gaming PC.
In other words: It just doesn't make sense to wait for a Mac version of a game. It will perform worse than the original, have more bugs, cost more and be years late.
Personally, I can only live with Macs because I have an Xbox 360 and a Windows license for my Mac Pro for those few (usually older) titles that don't have Xbox versions or that are strategy games like Civilization IV (whose Mac port by Aspyr sucks rocks, by the way).
My advice is this: Buy the Windows or Xbox version of that game, have fun with it and be happy. Don't waste your money on "supporting" Mac Gaming. If those guys delivered quality ports in a timely manner, my advice would be different. But such as it is, Mac Gaming is a dead horse.