
There is A LOT of difference. It's not just that MS has apps that come bundled with windows, it's that they have lines in the windows code to take on its competitors, that is, to prevent apps from competitors from working the way they should. This is part of the reason why the EU had them "punished"
Besides, Apple just gives you more choices, and better choices. Proof of that is that both IE and Safari come with OSX.
Another difference is that Apple uses industry standards.
MS loves to put their "twist" into everything and then once everyone has it they change it, they charge for it, and they control what happens.
Again IE is a nice example. They stopped developing for any OS other than windows... what about the losers who developed their websites to work with IE and don't have windows? That would suck
Besides, Apple doesn't include inferior apps with OSX. That can't be said about MS