I'm primarily a Win/PC guy; been building PCs from parts since Intel 386SX/Windows 286 days. I have all Windows units at home and office, except for the MBP.
I probably would not have looked twice at an Apple due to the cost difference and the "comfort" with Windows (warts and all), but I purchased a MBP for my wife to use for its "simple" OS. I've found that OSX as has matured, I can do almost everything I need in OSX, the multi-finger gestures on the touchpad make it easier/faster to do it, and the closed/sandboxed approach to maintaining control of the hardware and software environment results in a very stable/reliable platform. Combined with the top-level hardware (Unibody Aluminum chassis, wonderfully smooth touchpad), I'm starting to sip the fruit-flavored KoolAid.
And from what I've seen of Windows 8 previews, there appears to be even more reason to shift to OSX!