They are the best of the best. No doubt.
There are a couple of things that really standout about Grand Sport: First, everyone there is very relaxed, cool, and unpretentious. With most high-end shops the attitude can be quite off-putting, but these guys are very friendly. They make me feel welcome each time I go in. Second, David Lang's attention to detail is very impressive. I have never met anyone more fanatical about their work. He is the best of the best. No doubt.
I have used many independent shops in the area, including all of their competitors, and there is no question Grand Sport is the best.