Larue, American Defense and Bobro all make good units from the research I have done. Larue's are the most popular but I am going with a Bobro on my next build. I don't have one, but from what I have read, the Larue's will start to mare the finish on the rail after being removed and reinstalled a lot of times. It doesn't affect anything other than the looks, so it might not be a big deal to you.