I've ran an RMR type 2 on my duty pistol for the past two years. Great optic and I'm very satisfied with it. Two weeks ago we began transitioning the entire department over to MOS G17's. The optic that was chosen was the Holosun 508T with green dot.
We've ran about 70 people through the training so far great results. The Holosun offers several advantages of the RMR. Most notably is clearer glass with less distortion and the side loading battery tray so the optic doesn't have to be removed to change the battery. I've personally noticed that the green dot doesn't seem to starburst or flair as much as the red in lowlight, but that could just be my eyes.
I'm also running a 507c-x2 with ACCS reticle on my personal G19. Another great optic and I really like the reticle.
I've got no trigger time with them, but I'd love to try the SCS and enclosed emitter 509.
The RMR is awesome, but Holosun offers a lot for the money and has some distinct advantages, IMO.