It's not about "What's better" it's about "What works better for me"
I can do Ruby on Rails development in Windows - it's awful, but it's possible.
Same with web development.. it's just "better for me" in OSX.
Lots of things are better in OSX - sure, you can do them in Windows, Linux, whatever, but it's just not as polished at a lot of things I do.
It's all about what works BEST at a particular job.. and a lot of the things I do now are better on Mac for me - Fact.
I use Windows as much as I use OSX though.. as I use it all day at work. Why? Because the work I do, it's better on Windows.
And the price issue.. meh.. not again