I have purchased two of these scopes for different semi-autos. One 22lr (GSG 5 carbine) and one rifle a .223 cal with a lot of rails. I really like the 2x power and good field of vision. Very fast to acquire the target. If you don't have perfect eyes, these scopes are a huge improvement over open sights. The scopes seem to mount fine on Picatinny rails and hold their settings.
The red dot does seem a little star shaped if the rheostat is adjusted to bright. I am sure that buying a much more expensive red dot scope would have advantages. However these seem to do the job just fine and I might buy another.
Pros: 2x power, available battery size, good battery life
Cons: Red dot is not perfect
This review was written in the old system and had content requirements that are different than reviews written today.