Battlecomp, Dynacomp, and the Griffin M4-SD compensator - the performance of the three are about equal.
Battlecomp 2.0 ~$165
Battlecomp BABC ~$210
Spike's Dynacomp Extreme ~$90
Griffin M4SD Compensator ~$95
I have the Dynacomp on my 300 BLK, so Tom had to copy me.....