Here is a pretty good link on the pros and cons of the aquamedic reactor:
http://www.reefcentral.com/forums/sh...trate+reductor
Seems to me that it's a lot more screwing around than the pellets, with a much larger potential for crashing the tank. It also may be more expensive than the pellets.
I'll stick with the pellets, I don't think they are the miracle cure for everything but they are a piece of the puzzle.