They're good, but the new(ish) Leupold HAMR is just as good and durable with twice the eye relief. The ACOG is awesome but can be like trying to look through a coffee stir straw as close as you have to put your eye to it. Their DeltaPoint reflex sight on top (optional) is every bit as good and durable as the "doc optic" the ACOG's often wear on top. The ACOG never needs batteries I guess, the HAMR has a fixed reticle that's there even if the battery goes out. Both are great glass of course.