We are in america playing a shooting game. C-more red dot on a AR is the fastest as you can see more and shoot faster. There is a reason they use them on open guns. With 2 or 4 moa dot is is good to about 300 or so. Up close it is FAST.
Most branches of the U.S military run Aimpoint CCO's for their red dots. Its mostly spec ops guys who run Eotech ect unless a grunt feels the need to buy his/her own optic. So if you didn't like the Aimpoint on your M4 i recommend a Vortex Strike Eagle or any scope with a 1x power setting so you can still run it like a Red dot but still have the added magnification when you want it. If you shot expert with iron sights you won't have any issues hitting most targets at the ranged around here don't think anyone has a range that reaches past 300 yards in the metro area except maybe OKC Gun Club.