I had an rmr on my ar15. For some reason I couldn't shoot well with it yet when I swapped to an aimpoint I was able to do better. Maybe it was my sight, Bc it was my rmr01 which I'm the least consistent with. But my mac10 works just fine with my rmr04. Recently sold both my rmr mounts though. And swapped both rifles to MRO's Bc I was able to get them for significantly cheaper than an aimpoint t2
I find that pretty much any of the reflex sights with a convex lens makes for a slightly more distorted view. I find the tubular style red dot optics like the aimpoint pro or micro series to suffer from less distortion.