I'm already an OS X user. And I think it does a whole lot of things so much better that transition from linux to OS X has been painless. After adding macports and some bunch of open source software, the practical differences are:
1) ready availability of development environments like xcode or flash studio;
2) the ability to install and play some games on Steam.
3) 2.5x times the battery life I used to be getting with my linux laptop. (I'm mostly complaining about the significantly increased power drain associated with new kernel versions.)