Burris much better than Optima (Tasco & J-Point) Base fit snuggly with some filing to fit sight dovetail slot. Above reviewers should have filed the base rather than buggering the gun's dovetail. Much better than the Optima in holding zero, and minimal parallax. Optima(on RugerMKII) has 2-3" groups caused by parallax at 50'. RugerMKII with Fastfire will shoot 10 shots into 0.5" at same range. Change I would like to see is Allen or Torx adjustment screws instead of flat-blade on locking and adjustment screws. Locking screws are a real plus. Holds zero very well (1year and 15000 rounds with no need to readjust - except for ammo changes.)
Pros: holds zero, easy to use, locking screws, little parallax
Cons: dimming feature sometimes inconsistent
This review was written in the old system and had content requirements that are different than reviews written today.