I find Apple's use of the trackpad for swiping between desktops or between full-screen apps to be much quicker for navigating an environment than the alt-tab or mouse use on Windows. Perhaps Windows has improved to offer similar Apple navigation techniques, but I really like that when I switched to OSX. I also think Time Machine is one of best native OS tools I've ever seen, painless incremental backups with no effort by the user.
I came to like things about OSX also. In particular I liked the Ubuntu-style Spaces. That doesn't mean they were intuitive; it took effort to learn the Mac milieu.
