The TAPCO unit is simple, rugged, and will work on 90% of AKs 90% of the time. The B-Square unit is a little more complicated (separate parts to keep track of), but will work on the AKs the TAPCO unit will not (FSB/gas block combos like the AK-105, Krink, STG-2000, and some WASRs), and allows more force to be applied if you get one of those really stubborn windage drums. I have both types in my toolbox.