I've got the Norgon Ambi on one rifle, and I like it. I'm not sure yet if I like it enough, or would use it enough, to put it on all the other ARs. I'm right-handed, but shoot with both, so I practice both sides. Mag drops are definitely better with it, left handed, there's no doubt. Like any other weapons configuration change that you make, you'll definitely have to train for it to use it to it's designed potential. My opinion is that if I really need to make a mag change when shooting left handed, then it's paying for itself - I better hope that's the rifle I have at the time that I need it. If I need to make repeated left-handed mag changes, I need to find myself a better shooting position... <thumbsup> If you're left-handed, it will definitely benefit you. Troy makes one, but I haven't even seen one yet, much less used it.