So I have had the Glock 34 MOS for a year and a half now and I have ran it through numerous 3gun matches and 2 USPSA matches, it is a great pistol that offers all the benefits of the standard Glock but allows you to run various red dot sights with the provided adapter plates. Instead of paying to have your Glock milled you can unscrew the cover plate and add the appropriate adapter plate to your particular mini red dot. I used the Trijicon RMR RM01 3.25 MOA non adjustable LED. It is different using a red dot but I can see where it would be beneficial for hitting targets further out or someone with aging eyes. The Glock MOS can take many different sights but I recommend the Dawson precision sights as they allow you to mount your RMR and retain great sights. I have the non co witness sights but if I were using an RMR all the time with this pistol I would use the Co wtiness sights. The MOS line is the most versatile line of glocks because you can do anything you want to them with minimal tools. As much as I like the pistol I did find one glaring problem and I have heard of others having the same problem. Roughly after 15 rounds my RMR came flying off and hit me in the head. The screws that Glock provides are short and only 1 or 2 of the threads actually will lock in. I had tightened them down and the screws come with thread locker on them. I have ordered some replacement screws from Battle Werx so that I won't have this problem again. The screws provided by Trijicon are too long to use on the MOS. If you are considering buying a Glock and you want to in the future add a dot to your pistol I recommend buying the MOS and some Battle Werx screws. I bought two sets of replacement screws for the entire setup for 2 sets of 6 for $12.99. Getting the MOS package with the Battle Werx screws is cheaper than sending out to get milled however getting it milled will have a tighter fit because it is for your specific red dot while the MOS allows you to have any dot you can think of.