I trust my dealer to supply me parts and advise, i have never had them do any actual work for me, i have done it all myself.
I have a mate in salt lake that used to work for IM bobcat there, he got me loads of parts over the years while he worked there. There was one part i bought new, an aux hydraulic stem. It didn't work straight out of the packet. I needed to disassemble it and free the internals to make it work.
They are like a car dealer, they know their own brand, and they know them well and have access to service information we don't. For this they can charge more for the work.
Sometimes they will get it wrong and have a shitty customer, but i'd like to think that percentage wise, that is a very low figure. There have been posts on here by a few people taht were burnt by their dealer. They got a lemon machine from new and the dealer did little to nothing to help. Hopefully people know that dealerships are privately owned, the poor service you have at one is not the same as the other.