Two points to make here, the second tangential:
1. I've been using Windows 8 Pro since July and have had no problems with it whatsoever. The only software that I had an issue with was Alcohol 120%, but they have a fix coming and in the interim upgrading to SPTD 1.83 and re-installing Alcohol has it running flawlessly. Don't know what people are in such a lather about. I don't miss the old Start menu at all, just hit the Win key and start typing and my programs show up in a list. My main issue is access to the power commands but I've gotten used to hitting Win-C and selecting Settings. Cumbersome? Yes. The end of the world? No. I don't even think about it anymore. Everything else works fine. Having said all that, I don't see any compelling reason to upgrade to Win 8, so if you're on Vista or 7 and are happy, stay there. I wouldn't stay away from a new machine with Win 8 preinstalled, though, and I wouldn't "downgrade" such a machine, either.
2. Really peripheral to this discussion, but I feel compelled to note that my experience with Vista was great! Biggest problem I've encountered wit Vista and Windows 7 has been Windows Media Player Network Service...