Agree. Until you've used the touch gestures (even Apple's gesture mouse) on OS X to scroll through documentation or Perforce source trees or whatever you don't know what you're missing.

There's also the matter that for whatever reason, Apple's trackpad tracks the cursor movements better than any PC laptop running any OS I've ever tried. Even the Mac laptop running Linux or Windows isn't as smooth, so MJG's statement of the "hardware/driver combination" is true.