I personally do all of my development on a mac, and I used to be a Windows guy myself just last year.
A couple things come to mind when switching over to mac:
1. Better Integration
2. Unix based filesystem
3. Superior text editor
4. You can copy and paste text from the terminal window
5. no more EXE's! To install a new app, all you have to do is drag and drop to your Applications folder!
6. No more getting asked every 5 seconds if "you are sure you want to do this?" or getting told "You don't have permission" to use your own damn computer.
7. Oh, and things just work
Once you go Mac, you don't go back.
Unfortunately, this can be an expensive habit! Haha!