Bought one year ago. Have used it quite a bit on personal and work guns (it even has a couple of jumps 
). It’s a first focal plane scope, you can range and shoot from any magnification. Optical clarity is pretty good, the BDC reticle works and is illuminated; and it holds zero, period! Seriously, I have switched it back and forth with an RDS, on several guns and have had no problem zeroing, and no zero shift once zeroed.
I have used it to win several 3-gun and Tactical Rifle matches, and it works well for that. It was designed to be a more affordable option for a 1-4 combat scope then the S&B Short Dot, NF 1-4, etc, and from my experience with three of them on work guns, it does just that… Unfortunately only about 200 (I believe) made it into the US and were sold.
Here is a link with some info on the scope and the reticle specifically-
https://www.m4carbine.net/showthread.php?t=3131&highlight=GRSC
And here is some pics of the scope and reticle-
Scope before I cleaned it (SPR-E mount not included)
Mounted on gun going to work
Ocular lens
Objective lens
Reticle at 1x
Reticle at 4x
The outside has some scratches, however they are all cosmetic- the lenses are perfect. No nicks, scratches or smudges.
The only one I have seen sold went for $450 OBO. So we’ll start with that… “First I’ll take” it gets it.
I’ll post it here for a few days then will put it on TOS, as they’e begging for them. I would rather someone here (esp. a Soldier, Sailor, MARINE or Airman) that will use it to have it, then a hobbist…