This year I added a EOTECH 512 to my Remington 870 SPSt. I really like the setup and hesitated for a long time before finally taking the plunge of adding optics to my turkey gun. I'm hard on stuff, and tend to take the KISS approach to most things, but after a few misses from shooting in awkward positions, I anted up to the world of optics.
The site dialed in quick and I only spent about an hour on the range getting it tuned in. I was also astonished at the before and after differences of shots inside 30 yards. With the built in iron sites, it is very easy to cant or torque the gun and send the pattern 6-10 inches off in any direction, yet it still appeared to be a good site window. With the EOTECH and it's parallax free design, the shot goes where the dot is, period, no matter how you hold the gun!
One of the benefits that I have discovered is the aid that this site provides in helping to estimate range. The 65 MOA circle represents 32.5" at 50 yards. It happens to also represent 26" at forty yards.
So here is the method, if an erect gobbler fits inside the circle, he is beyond 50 yards. If the circle touches the tip of his head to the bottom of his feet he is at 50 yards. If the circle covers 2/3 thirds of his height he is at 40, if the circle covers anything less than 2/3 of his height, he is well inside 40.
Wish I would have put this on a few years ago