I work on/with both PCs and Macs everyday (for the past 2 years). From a reliability standpoint I really don't see any difference at all. I've gotten the Mac spinning beach ball of death more times than PC blue screen of death on either of my work or home PC -- make that both combined -- and they're all about the same age.

There are definitely things to like about both, but when I want to be productive, I still go back to my PC.