I have a gamo that I like. I have had 2 of their scopes, the red dot and reg scope. I have not been satisfied with either. I have had to adjust the regular scope a couple times. I have tried to find open sights for mine but the only way I have seen them is on a new gun. As far as power it is very adequate.
When I was a kid a friend had a Bennjerman and I always thought it was the best but it was a pump. They have been around a while.