With the caveat that the latest OSX releases broke Atom CPU compatibility and you've really gotta pay attention to what you're doing before hitting the 'Update' button.
I run OSX on a C2Q machine I built for $450. Works great with everything working 100% except it's not quite the same seamless experience a real Mac is (I've gotta fix my sleep mode nearly every update).
It's basically a hobby project. You could arguably save a few $k building a Mac Pro clone, but if you really need a Mac Pro level machine then you probably shouldn't rely on a Hackintosh. It certainly kills the "just works" aspect of Apple products.
I run OSX on a C2Q machine I built for $450. Works great with everything working 100% except it's not quite the same seamless experience a real Mac is (I've gotta fix my sleep mode nearly every update).