I use it all day, every day, for gaming, work, general use, etc., and I have no problems. The only time I started to get a sore wrist was after five or so days of gaming with way too much (and I mean WAY too much) clicking. That one time aside, I never get any pain. I don't find it comfortable, and it doesn't bother me. Although, I wasn't sure about it and did think I had made the wrong choice during the first week. I forgot about it eventually though.
I'd suggest trying it out in the Apple Store, if you can. Maybe even have a go of a friends? Etc.