Ive been trying my hardest to avoid this flame-ish topic, but this morning for some reason I can't hold back anymore. The most important difference, IMHO between using a Windows-based machine and a Mac is the way that the operating system handles I/O and its virtual memory handling. Back in the day macs were far superior to windows machines because it was easier and more sane to have control over virtual memory. Of course, this was in the pre OSX days and the tradeoff was that there was no real multitasking, etc, etc. Classic Mac OS was a nightmare for reliability in alot of ways, but the nice thing about it was that it was simple and easy to control/configure. By comparison, Windows 98 and even 2000 and early versions of XP were horrible about their handling of virtual memory which caused you to need better hardware to have comparible performance while recording. 
 
Of course, things are a little more complicated on the mac side now. It seems like virtual memory isn't as big of a performance hit as it used to be and its such an integrated expectation of the operating system anymore on both sides that its hard to make it much of an argument (except what handles what better). I haven't used windows in ages, so I can't say I'm any expert on the topic. The point is that theres nothing magic about a mac or a windows machine that makes it better or worse for one application. The only point is how the software interacts with the hardware and how much hardware you need to get similar performance. My guess is (based on historical evidence of microsoft's inability to stay with the curve) that the Mac OS still is going to give you better I/O handling and better virtual memory performance. 
 
But really, seriously, theres no magic here. There's no secret sauce.