Embarrassing to admit, I've never had my Viking in for service in the 10+ years I've had it. I actually love the repair guy at the dealer where I bought it, and have taken other machines there for service. Never have an issue with them. Regular service is about $100 and they include minor issues in that fee. They always call for authorizations on other things they might find and the turn-around time is always as specified. Honestly, I don't even know of any other repair person in the area! But I've used this shop for the 20+ years I've lived here and always very pleased.

I usually do as much as I can myself, then get my son to look at it before taking my machine anywhere. There's not anyone close by (less than an hour drive) and I don't really know anyone to ask about who to go to. Seems like the going rate for service is pretty expensive so I try to just head problems off ahead of time.
Used to be able to find someone fairly easily, but many of these fellows have retired or passed on. The last guy I took mine to was in his 80s.