Arthur P stole my thunder! I have tested a fair number of heads, and to be honest most have been at least acceptable in preformance. The few exceptions have all been Satellite head, with models ranging from the sat mag' s to the titains and the " dead ringer" mechanical. All have been down right bad. Another head to stay away from is the Pucketts blood trailers. The New archery products " new" Razorback was also junk, or at least last years model. I understand this year they have improved the head. Rockets Ultimate steel was also unaceptable, it lost blades very easy is targets ranging from soft foam to steel drums. I am sure their are a couple more but these are the heads that first come to mind. Companies like Magnus, Muzzy and Rocky mtn have all made heads that ranged from good to excellent in my tests and none of these companies has so far put out a Lemon.