Unfortunately for the good technician the first line of defence for a person off the street is the service writer. From my past experienced the service writer is for the most part arrogant/ignorant. This has a direct reflection on how I perceive the work done at the dealership.
I usually end up at the parts department standing in line with technicians. One soon realizes that the technicans dont have the same arrogant attitude as the service writer and they put their pants on the same way as everyone else.
Walking to the parts counter you often get a chance to see the shop floor where the work is being done. My take on a good shop is if the technicans are working at a comfortable pace - not rushed to keep up with the backlog or not too slow so the customer isn't paying $85/hr for the technican to do a 2 hour oil change.
I am not biased with the dealer or independent, but I do appreciate it if I am told about potential problems with my car - something that you cannot get at a quick lube oil change.
The shop I go back to is the one which stands behind their work and charges fair prices.
1998 Mercedes E320, 200K Miles
2001 Acura 3.2TL, 178K Miles
1992 Chevy Astro, 205K Miles