I like OS X , a lot, I'm not even comparing it to Vista, it's a different thing; some things are a little different, you get used to it; others way better than MS Windows, and you will never want to go back.
I was giving a talk last tuesday about design in UI and Interaction design, and the Mac environment is very cohesive and consistent, some things I had trouble adjusting are the keyboard and the whole file manager : explorer vs. finder , finder has better search: it works as opposed to the windows "Search" in XP, the keyboard , still not convinced....
The quality of the hardware is top of the line, some bundled applications, like Mail, Dashboard, iPhoto, etc are really good , other are more novelty items. I was, however, very surprised by the number of open source and freeware applications for OSX , Adium(IM) , TunnelBlick (VPN), Skype, Mac the Ripper ( DVD backup) , Transmission ( Bt client), even Microsoft's remote desktop, and Apple's Bootcamp ( very important because I work in XP so I need dual boot) work very well.
- Uninstall = Trash
- iLife / Automator / Unix
- Hardware design
- No drivers ! No dlls !
- No NTFS writing ( at least not officially)
- too few USB ports
- No memory card reader
- You need an external mouse for windows XP
- Awkward keyboard layout ( for a PC user)