my old man used them on his car and you can't even see the key mark that wa sin the side of his car. excellent service and I don't think it was too expensive either and he was well chuffed
Did a good job on the smaller marks and paint chips on my silver bullet, but couldnt grade the new paint in so well on a larger ding I had on my door. If you stick to the smaller stuff, they should be OK.
We use them constantly for our business. They are a franchise operation so I guess it depends on the quality of the particular franchisee. The guy we use is very good and good value compared with the manufacturers' service & body repair department.