I've had mixed results with pretty much every dealer out there. With the Vette, they always need to "order" parts. Even AC switches... I ended up going to a friend's used car lot and pulled my replacement switch off of a sedan a customer had totaled.
As for other dealers, I had a decent experience with the Nissan dealer in Winter Haven. I went in to have my AC and cruise checked (neither was functional). I got charged a fee (that would be deducted from any other work charged) to check it out. During the check the dealer changed a few switches, vaccuum lines, and a wire and got the cruise fixed for no extra charge.
Then they said that it would cost $3700 to fix the AC...
My father has had good experience with whatever Jeep dealer he goes to. He has a 4.0 Cherokee, so there's not much to fix though. I wish all American cars were built like that Jeep, I'd stop trying to convince my father to buy Toyotas.