I've been carrying a Glock 19 as my primary EDC for over 20 years, first a very early 2nd gen, then an OD 3rd gen since 2005. The only other guns I carry are a 43 as my BUG and a 48 when I need something slimmer for days when I have to dress up. I've been wanting to try a red dot on my carry gun for a few years now. I finally ordered an RMR RM06 Type 2 over the weekend. Now, I have to decide how I'm going to implement it into my carry. I'm very happy with my current pistol and if I could buy a factory gen 3 MOS slide like Glock sells to the military, I'd do so today. I like the finger grooves just fine and I prefer the trigger to the gen 5. I know most people just buy an aftermarket slide with an RMR cut but I'm not thrilled with this idea for a carry gun. My 19 has been 100% reliable for over 60,000 rounds. The only parts I've changed out are other OEM parts like the smooth face trigger bar and minus connector. Changing out a major component like the slide doesn't appeal to me. I'm also not interested in having my slide cut. I love that gun and the idea of having it milled and refinished makes me a little nauseous. I do like the MOS concept as being somewhat "future proof." That basically leaves me with three options: 1. Buy an extra OEM gen 3 upper and have it milled. The downside to this option is that I'd likely end up with as much or more invested than just buying a new MOS gun. 2. Try to track down a gen 4 MOS gun as a "compromise." A new gun that's RMR ready but feels more like my gen 3. The downside here is that the gen 4 has been discontinued and I don't know how long it will be supported. 3. Bite the bullet and buy a gen 5 MOS and try to learn to like it. The obvious downside here is that I don't care a whole lot for the gen 5.