Only big difference is there is no Unlimited on Mac, and some plugins don't work (those usually require Windows-specific code). Otherwise, they work the same. Heck, you can even use Control shortcuts instead of the Apple/Command key.

There are actually a few neat things you can do on the Mac version of Maya that you can't really do on Windows (that I know of...):

1) You have access to an additional modifier key, the Command key. For you Windows users, imagine if you could use that stupid Windows start menu key on your keyboard for addition hotkey combos. On my Mac, I've created hotkey combos using control, option (alt), command, and shift. I miss that when I switch to my PC.

2) You can tear off menus from the Hotbox. I don't use it much (hotbox is a bit slow for me on the mac), but it can be handy sometimes.

3) Transparency is supported on shelf buttons. Basically, the shelf knocks out the neutral gray color if it is present in the shelf button image. Subtle touch, but nice.

Mind you, none of these are essential. They're just kind of cool.