Eotech is the leader in holographic gun sights and the EXPS3-0 is a great sight for the AR-15 or other tactical rifle. It’s light weight and very compact. It’s super easy to mount and remove. The EXPS3-0 only uses one battery which allows it to be smaller and lighter.
Eotech holographic sights are well made and last a lifetime. There is a reason the US military uses them in Afghanistan. They are tough and reliable.
Every review I have ever read on the Eotech holographic sight has been very positive. They are simply the best there is.