OS X is just smooth, it just works, iOS and OS X devices just communicate with each other to print, share files, share video, etc. Everything is interconnected. There's a polished feel. Compare that to Windows 8, where you get this guy interface where everything get's a box no matter how insignificant it is and there's this jarring desktop that pops up when you run non-metro programs. Not that you can actually do anything with the desktop, mind you, except drop some shortcuts, but it's still there. The whole thing feels unwieldily.
Bit off topic, but I've always been of the opinion that popular OSs should have two interfaces one for the advanced user and one for the general public. I guess metro will be the start of that for MS
Advise not to buy a computer for a pending sfw release.