You're asking a mac user why a person would be better off using anything other than Microsoft wmp? hehehe Other than their licencing of content & requirement to pursue other codecs. Wmp won't play all movie files on its own. Other apps will. Since MS are hand in hand with the RIAA & are all about licencing & maximising profits, the smell of wmp & its inconvenient error messages when you're wanting to play a particular file are enough to say, hey there's also more user friendly apps out there. Hey I was starting to get worked up on that! hehehe it must have been the smell of M$