I cannot speak to the ACOG, but to the EoTech. I started out with a big scope on a AR carbine. The scope always seemed too big and out of balance for what I was wanting to achieve in a carry gun.
I hunt the Texas brush country and seldom have the opportunity for super long shots, so I switched to the EoTech. It restored the balance and lightweight I was looking for in a coyote carbine.
Sometimes I am tempted to try the 3x with the flop-over mount, but I always tell myself that it is a slippery slope. Once I go back to the magnification dark side, I will not be satisfied with 3x and before you know it, I will be right back to some big honking tube again.