Darn Paul, I was going to skip this one. Then you asked and I wrote for about twenty minutes addressing the issue and damned if they don't shut the site down for maintenance and its all gone. Here it is in one line: Good techs are where you find them.
I truely believe the best techs are eventually at independents as most techs are not institutional players. Just check the average age of the techs employed where ever you go. The dealers train them and usually within ten years the tech can't put up with the politics necessary to make a living. (This often has very little to do with technical skill.) Warrantee doesn't hardly pay for diagnostics so the skill is poorly rewarded at the dealer level.
Dealerships offer the added comfort of manufacturer back-up, but independents offer choice.
I see that the largest wasted expence in auto repair is not dishonesty or lack of training (although both do appear at every level). It is diagnostic intent. To give an example, last week I worked on a 1999 528i for the SRS light being on. Testing showed an intermittant in the signal from the pass seal ocupied sensor. Having done a couple 210 cars with similar problems I might have replaced the film that goes between the upholstery and the seat as with the MB. Since I follow and contribute to the BimmerTG (a tech group for BMW technicians) I recently read that on Bimmers the seat film is connected to the harness by a cheap module/connector ($35) that is the common problem. Upon checking at the dealer we find that both the film and the connector are stocked as they always replace both pieces. Well the film requires seat disassembly and costs five times as much. I replaced the module only.
This would be considered poor practice by many managers as it could cause another trip for the consumer and leaves a lot of money on the table. A good independent has the access and freedom to use many techniques not available to dealer techs, from used parts to reconditioned parts (both done internally and purchased elsewhere). We repair Becker and VDO electronics and speedos for many dealers. We make A/C hoses. We do MIG, TIG, and gas welding and fabrication. We do numerous machine operations, none of which would be an option at a dealer. The fact that we can do these things does not keep us from being parts changers it just gives us another option.
But I'm biased!
Bosch Master, ASE Master, L1
33 years MB technician