Well some are rubbish, some are good. My one is good. Never had an issue before. But then again, I go in knowing what needs to be done. Wouldn't let them do work on my zed though. Did on my last car.
Oh and they usually try to fit pads and discs at the same time, so you can't blame them for the brakes messing up. If the discs are within a certain limit, their company policy is not to replace just pads. Its all because of the blame/claim game many people like to play, I'll sue you etc. Avoids them getting sued. But they also offer the lifetime replacement warranty included for free to counter act this.