I have a 30 coercer, by no means a high enough level to really get the complete feel of it. But having one in my group as a main at level 70, makes the difference of running an instance in 15minutes and running one in an hour. The can up DPS, power regen, and lots of other fun things. Good on raids, and IMO a highly needed class.
However, it is difficult to play. Without a good tank and healer, you will die alot.