I have heard bad reviews on them from several sources, as well as opinions of shop owners towards them also. My beretta u22 neos hasn't jammed once, and has been VERY accurate at 25 yards(6in barrel). All 10 rounds are in a 6in circle every time, and I'm still dialing it in. It's cheap and quite effective as well as easy mounting of whatever sight you want due to the big ass rail on the top of it.