"Comfortable" is subjective. You should try both yourself.
My personal experience is that no mouse is comfortable, and I can only use a trackball or graphics tablet for long periods of time. Intermittent trackpad or touchpad use is ok, but 5 minutes with any mouse and I'm in pain.
Honestly for me neither. I prefer either the Microsoft 7000 mouse or the logicitech revolution line. That being said I use a magic mouse with my mac because we'll it is supplied by work and I do not have the money to go out and buy the revolution right now.