On the other website that was mentioned, the CEO stated that they were phasing out the Docter3's due to lack of demand. Everyone was asking for RMR's so that's what his company was going with, even though the D3 tested better and had some advantages over the RMR.
I have a Docter 3 on a G17 that I've put 800 rounds thru. Still learning, but so far I likey.