It really depends on the dealer. So generalizations should not be made. Just because a couple people here and there have had poor experiences with their own dealers, does not mean that all dealers should not be trusted or are "stealerships."
Very true. And the statement about bad management is true. My dad has been a mechanic before they preferred to be called techs. Actually, before I was even born. Due to how poorly a lot of dealerships are run, and how poorly the dealer industry as a whole appears to be run, mechanics move around a lot. I think my dad has moved 9 times. All for one of two reasons: 1) not enough work or 2) management sucked (not paying bills, making it impossible for techs to do their job).
Most dealers allow you to request that a particular mechanic work on your car. If my dad knew somone who needed work on a brand he was working for, he'd have them bring it in and make sure they ask for him. If you can build a customer relationship with the mechanic, you might be able to get around the service writer, sorta.
What my dad has found is that service writers are really just sales people. When he diagnoses a car, the protocal is to tell the service writer what needs to be done. The service writer calls the customer and gets permission to do the work. The problem is that the service writer likes to add a laundry list of services designed primarily to drain your wallet.
So, if you find a dealer with a good mechanic, try to work more through them than the service writer if you can.
If you can avoid going on a Saturday, you'll probably get better work. Since a lot of people work M-F, Sat. is the day they can take their car in. If the place is crazy busy, the techs are rushing in order to keep the customers happy. On the weekdays (non-holiday), they are usually slower, so they don't rush around as much. You'll be more likely to get a decent look over the car as well as the service requested.