Drury:

I have a friend who uses his Mac extensively and HAS developed Carpal Tunnel Syndrome. I'm not sure whether the mouse or the keyboard is to blame, but you clearly have to use your Mac A LOT to develop this problem.

I don't know for sure, but I would suspect your desk and chair might be more critical than the shape of your mouse. But if you get up and take a break every few minutes, and don't over do it (except when writing voice cards), you probably won't have any problems.