I'll be regression testing Reliabit's Mac games next week on Snow Leopard.
I purchased a new 1T Barracuda drive. Its amazing how cheap these devices are these days. I've created new drive partitions that I can use to test different versions of the Mac OS. Real easy to install on my Mac Pro.
The price of the OS upgraded is nice. But the real issue that worries me is what mac apps might be incompatible which would trigger more unintended problems. Another reason just to go the partition route.
Though, I suspect if there are going to be problems with the current games it might be the HID stuff or the graphics cards getting taxed from OpenCL. Yet, most things I've read about OpenCL indicate that it should not hamper the graphics cards performance. Of course, the main source of issues tends to be all the myriad of drivers which makes it such a pain. Makes the iPhone development that much more compelling.