I've used RMR's in the past and couldn't find the model I prefer in stock for this build. So for a little less I picked up a Razor 6 moa MRDS and I have to say I am pleasantly surprised.
The first thing I noticed is that the FOV is HUGE. WAY bigger than the RMR. You won't know what you're missing til you look through it. Small FOV on an optic like this is not typically an issue,, until you take into account the the RMR actually BLOCKS FOV.... for me that became an issue when I realized that the Razor just "disappears".
The glass is tinted a little on the blue end of things... weird but not a real issue for its intended use.
I prefer the rear mount to the front rail. Tried both and rear is WAY faster acquisition. Maybe just me.
It has a battery tray that slides out so no re-zero. LED turns off after 5-6 hrs. automatically. This is probably the only downside for me as I prefer "always-on" RDS, but it IS a supplement sight. Battery life is claimed at a year, but I've only had mine a few months, so cannot comment.
It is as bright as my Aimpoint PRO in bright daylight. No issues there. And it can be found for about $120 less that the comparable RMR.
It has a lock screw for after zeroing and seems built like a tank. I have... *blush* dropped my rifle on it twice with no negative impact (pun intended) or change in zero. Add to this Vortex's VIP warranty and I'm sold.
John