My local Stihl dealer is part of Ace Hardware, they have a service center run by an old Viking looking guy who knows his stuff, and parts on the shelf. I'd let them work on my stuff.
I bought my 500i from a Coastal farm store. They have a service center, but this was the place that tried to tell me that pro equipment had a 90 day warranty period, no matter if used for commercial or personal use. They also never registered my saw with Stihl. I got Stihl corporate involved and they took care of me, but I wouldn't want them touching my equipment.