nothing really although i'm not that familiar with it. i've never had one but i like to play around with the ones at work.
Windows is just better. It is a lot more compatible with software, hardware, etc. It's easier to use.
There is software to do pretty much everything you do on Windows on the Mac. Sometimes it's not the same software but there is usually something out there.
Macs are overpriced.
I agree. They are priced higher than similar specced machines, but I do like the aesthetics and general design of their products. That said, if I could put OS X on something like an HP Envy 15, I would probably do that over buying a MacBook Pro.