The only differences that I see is that the Color scheme is slightly different than the PC version, and that it doesn't come with a USB 2.4 dongle, which IMO is not a good thing, as sometimes bluetooth fails (after a bluetooth driver update for example) and you might need the USB 2.4 dongle to get things working with bluetooth again... (though the USB cable part is available, so that might reduce the need for the USB dongle). Or maybe you want to connect the keyboard or mouse to a non-bluetooth device every once in a while (one of the reasons why these devices can be programmed to connect to up to 3 devices).
I don't know... unless I really want the colors to be different, I'd just go for the PC version, even if I'm on a Mac, since the PC version works with Mac without issues and actually has the OS X buttons built it.