I have a magic mouse that came with my iMac and I've been having issues with it on elementary OS. The greatest problem is that it disconnects way too often. My mouse also moves way too fast, even at the slowest speed it's uncomfortably slow. None of these problems are an issue on Mac OS X. I've dual booted so there is no hardware differences.
Even though I don't think it's necessary:
iMac (21.5-inch, Mid 2011)
Processor 2.5 GHz Intel Core i5
Graphics AMD Radeon HD 6750M 512 MB
Memory 4 GB 1333 MHz DDR3