Well seeing as there really isnt much pinpoint acuracy in airsoft I would say eo-tech, but saying that I usualy use an aimpoint replica, and I think ive actually turned it on once, I ususaly just end up aiming in the general direction, however Ive never really used an a-cog replica so i cant say how good they are, I've used a Trijicon at the range a few times and it was cool, I dont think id spend $1,000 on one though...