I have one, my brother has one and several of my friends have them. I have a dedicated .22 upper on mine right now but have also used it with 5.56 and 6.8 uppers. Everyone else is using them with 5.56 uppers. We have at least a few thousand rounds total through them. None of us has had any problems and the fire control parts, though plastic, make for a better trigger pull than most standard AR's I've had. In my experience, they're a heck of a deal for $99.