It's great to use a one piece mount. You eliminate a couple steps when mounting. You also do not have to guess at which height of a certain brand's rings to use for your AR. They all have to make their ring sizes mean different things. High in one is equal to medium in another or ultra-high in another. This is just The Correct Height For An AR-15.
Pros: Very easy to mount a scope with one
Cons: None!
This review was written in the old system and had content requirements that are different than reviews written today.