Having run a number of heroics on my mage, with all of the different healers, I have worries that Priests can't keep up.
Having run a number of instances on this Priest, I think our mechanics are the most poorly designed part of this game (really? create tightly tuned encounters, and add a 30 sec debuff of choice called chakra on top of it? Fun? No. Clunky and horrible for serious progression? Yes.)
So, how bad is it? I know some people are raiding.