Rmrs are great.
The deltapoint pro is better... Let me explain...
Dpp has a larger window and the triangle reticle gives you a point for a zero and the body for doing work up close.
Rmr is considerably more difficult to find, at first... Repeatable, consistent presentation is the key... That takes time.
I did dpp. I don't regret it. I have gotten better,/faster with a red dot (orange in this case).
My 2cents.
For my experience, I hated slide mounted optics. I did the Um3 system with their holster. Looks hokey, it's not. Toooooooo me anyway.