I have used him. I don't know how well he does with EFI since I have an Evo but I was happy with what he did for me. I saw him at 2 different events and he had a long line of people waiting for him. See if he is taking appointments on his web site. The sign up sheet at the events fills quickly.
I don't think that I would take my bike to an event to have it dynoed. Seems to me if the guy has a waiting line he might be inclined to hurry your tune. I have heard that some bikes can take 3 or more hours to get dialed in. Will this guy give you that much time with a line of people waiting? Just my thoughts!
Believe me, you have nothing to worry about with John. He and his wife schedule the time that they need with your bike. If he needs 3 hours then it is scheduled. The reason he has a line is because he is just that damn good!!