Anyone, be it someone with a forecourt, a main dealer, someone who trades from home or a road side trader can do an honest fair job but also anyone in the chain can do a bad job. It's a case of being 'Honest' with how you do a job. Painting one element of the motor trade as the lowest of the low is just defelecting the fact that there are rogue traders all along the line.
Myself I perfer to focus on my business and doing that right, yes I look at my business rates each year and think a roadside trader doesn't have that expense, but I also see Main Dealers offering to service a car for £99 or £149 and I know it's basicly an 'oil change' rather then what I would consider a 'Service'.
If your in it for the long term you need to back yourself, the bad traders get found out it just take time.
Would we all be better trying to get Trading Standards and the Office of Fair Trading to sit and listen to us, show them that a flexible approach is needed as the mechanics of a car is so complex that customer expectations need to be realistic.