To experience a main dealer you have to go to them with all youre motoring needs. It all comes down to expecatations.
If you go to a main dealer and get youre routine service done and then when you get a problem with a car you get pushed to the top of the list of breakdowns, a replacement car etc. Then your experience with the dealer is better but hampered by the fact your car has broke down and now is going to cost you money.
The flip side of this is Fred in the shed services your car, then when something goes wrong and he/she cant fix it, they lob you off to the main dealer. And then you give out about your main dealer because your car was last on our list to do.
We take care of our loyal customers and give the best service we can. You forget about the service Fred in the shed gave you, happy to take your money for the easy service, plugs, pads etc but when your car gives you trouble, he/she doesnt want to know about it. Then the Dealer is the bad guy.
Search the different threads on this section and you'll see all the people left high and dry by the "local or friendly mechanic".
Main dealer is not perfect but better than a non dealer.
Ps. Sorry for rant, I'll get off my soap box now.