Eotech 556 works great - EOTech 556 A65 Holographic Weapon Sight HWS

This is a great sight, fit perfectly on my AR. It's a little pricey, but you get what you pay for. It came pretty much zeroed in already.
Pros: Easy to use, reliable, perfect for booth eyes open shooting and can easily be co-witnessed.
Cons: Expensive, holographic sight looks a little grainy.

This review was written in the old system and had content requirements that are different than reviews written today.