I would have to argue that that's not really the case, at best they'd work the same on machines with similar specifications. The reasoning for that is quite simple, Mac's ARE PC's, and have been for a couple of years now (they made the Intel switch back in 2006).
Of course, I said AT BEST here. Unlike Microsoft, Apple has no obligation to support any hardware in their configuration other than their own, since they never claim that OS X can run on non-Macintosh platforms. As a result, you can run into driver issues if you don't hand pick your PC components to match what Apple uses to some extent.