Well...
I think I have some basis of knowledge regarding OSX and Win 7 since I have been using both for over a year now.
First, Win 7 is a terrific OS...the best MS have ever made. It is fast, stable and has a significantly smaller footprint that Vista. The UI is an upgrade from Vista and has many new features that even Mac bigots on this board have commented favorably on. I am running Win 7 under VMware Fusion on my MBP with 4gb of ram and it works great. I also have it installed on a 4 year old Sony Vaio with 1 gb of ram and an OLD processor...and it is fast and stable on that platform as well.
Is it better than OSX? Subjectively, no. But it is damned close to being comparable. And for those of us who need windows for work or if you need a gaming computer, well, Win 7 is where you'll need to go.
There is a lot of hype about Win 7 vs. Snow (Snore?) Leopard. Vista to Win 7 is a big deal due to the speed and stability that was lacking in Vista. OTOH, from an end user perspective only, 10.5.8 to 10.6 is not that big a deal regardless of what the Mac zealots say. It is an OS that has a grea amount of internal improvements to build upon but no big improvements in UI or performance except for the start up time.