hardware, then you are correct and it's not much of a comparison. But what if all your digital video and audio content is in itunes? if you own an iphone, then there are additional features they build between mac and phone that you can't get with a PC (Airdrop, wifi synching come to mind). Own an apple TV? then you can bring all your iTunes content to the big screen and you can share from your phone to the big screen.

Sure there are plenty of other ways to duplicate these exact functions and plenty of arguments about which one does it better . But in the ecosystem, Apple does all of them and for the most part pretty well and it would be a pain to try and piece together piecemeal all you get in the ecosystem for their premium.