I recently retired after over 26 years of service as a Navy SEAL. I was issued one of the first ACOG 4x scopes ever issued in the military back in the late 80s not long after they were first designed. I had one on my M4 during all of my tours to Afghanistan and Iraq as well. There are many servieable scopes and reflex sights available for AR varients. Some best suited for close-quarter battle, others for intermediate range shooting. All things considered, I personally consider the ACOG as the finest optic of it's kind ever developed. It is adequate for close quarter use, especially if equipped with a small reflex sight on top as some ACOG models afford. But from distances from 30-300 yards, rapid and precision target acquisition, it is superb! I have swam and dove them in salt water, jumped them from high altitude, carried them in the most extreme environments possible. Never have I witnessed one fail. I personally have found the standard balistic reticle to best match 55 gr M193 ball ammo. But recommend each shooter tailor his bullet drop chart to his specific weapon, barrel length, etc. But for center mass hits, it is very precise and effective. The tritium illumination transition from light to low-light shooting is awesome and unparalleled. That is the ACOGs strongest feature. An Aimpoint Comp is fast at close quarters, yet battery dependent and will fail in extreme circumstances. At 100-300 yards the ACOG is extremely effective, offering far more precision and utility than red-dot sights. But as I mentioned, the durability of the ACOG is comparable to me to the Unertyl sniper scopes I have also used in the past. Literally bomb-proof! Considering you likely paid between $700-$1,200 for your AR, the ACOG is expensive. But you will only need to by it once. It will out live your AR. It is my first choice for general AR applications, and I will stake my life on it confidently. One alternative optic I also have great confidence and experience with that is a much more affordable option, is the DMS scope made for the AR by Millet. Although heavier and larger dimensionally, it is also very durable and versatile. It operates on batteries yet has a conventional reticle also. The reticle is simply illuminated for low-light use, yet it offers flexibility for close, intermediate, and fairly long range use. It also has a form of ranging reticle for estimating distances. In my opinion, the ACOG is one of the finest combat optics ever designed. Thank God our enemies don't get issued them! tdv