While the idea behind pie menues has its merit, I simply don't like them. They say you can select an option faster, but in my opinion it takes longer to read all of the options (who reads in circles anyways?)
The idea just seems a little too funky to me, and its too different from how nearly every other system works. I don't mind change, but for me this kind of a change would be too much to have what I would consider a smooth-flowing UI, and I think there are plenty of others that would agree.
It'd be interesting to see everyone else's feelings on this as well.