I would take a look at the SS 1-4 as well. I am thinking about switching to one at some point over my Aimpoint, and I love the Aimpoints on the ARs. I usually just use the Aimpoint by itself, but now and then I borrow a friends flip magnifier and run longer ranges with it, but the SS 1-4 circle reticle has my interest.
Edited to add, I like the Aimpoints better than the ACOGs, but that is just my personal preference. Never cared for the ACOGs when I got to play with them, and didn't care for the price.
Edited by helo18 - January/30/2011 at 16:26