I wouldn't buy it because I already use it on a Power Mac G4 all day long.
I've never been impressed with any version of Windows - NT4 and W2k were quite usable, however. OS/2 pretty much ran circles around Windows where flexibility and usability were concerned. There's still so many little touches that OS/2 just *got right* that I still don't see on the Windows platform.
OTOH, for my own personal tastes and way of working NeXT/OPENSTEP beat them all hands down...and since OS X is the closest I'm ever going to get to that type of usable system today, that's where I'm spending most of my time. In fact, the only reason I even log in to my Windows machine these days is for customer support and to fiddle with a few skinnable apps.
OPENSTEP has been impressive for well over 10 years and OS X just builds on that beautifully, IMO.
I also tend to think that Apple will not release an x86 version of the OS X client. They ARE a hardware company after all, and it just doesn't make good business sense... OTOH, I could see them creating a special release of OS X Server that ran on a very specific type of x86 hardware. This might help them make inroads into markets that would soften to the idea of Mac hardware clients later.