There aren't any differences that I am aware of on the Windows version of Photoshop and the Mac version of Photoshop. You say "there must be something better" ...erm what do you want it to do that it can't? Photoshop is used by many if not all graphic/photographic professionals, maybe theres a feature that you want but don't know is there? If you ask, maybe someone can help you.
Incase you are thinking of buying Photoshop, Adobe will be releasing the Creative Suite 2.0 in the coming months/weeks. It will definately be out within the first half of the year. (I think they said first quarter?)
Anyway my point is that you don't really want to be dropping that kind of money on an app suite thats just gonna be updated. BUT as soon as they announce a release date they should give you the update for free. Thats what happened the last time, you bought the current apps and they had a sticker on the box saying that you were entitled to the new version and that it would be shipped out to you.