I don't know anything about Rock Shops, or what makes a good one or a bad one, however I will say that this place is awesome. Spoke with the owner and he is a 3rd Generation owner which is great.
We were there to pick up some things for my Nieces birthday and she is absolutely crazy about rocks, minerals, fossils.
They have everything from 50 cent pieces to 15,000 dollar full sized fossils.
It was a cool experience, definitely wakes up the kid inside of you! Worth popping in and checking it out!