This is too funny. It’s just like the internal iPod speaker, which makes nary a noise but that scrolling click (or if you’re adventerous a startling little squawk in devmode).
The two buttons (FINALLY), touch sensitivity, and the scroll ball are all decent additions. (wouldn’t quite call the scroll ball an innovation seeing as the whole “scroll from mouse” idea was borrowed from Microsoft). I wonder, though, how effective a ball is versus a tiltable wheel you can hold down, seeing as fingers tend to be much longer than wide.
The only criticism I would mention is that customization is only available under Tiger. This is the Safari 10.2->10.3 fiasco all over again. It seems forced obsolescence is worth the negative PR for Apple. As much as I love Apple’s design this is up there in the list of most irritating things a company can do to its loyal users. There is absolutely no reason why Apple couldn’t have supported older versions of Mac OS X. Cue an upstart shareware developer?