I recently had my sewing machine tuned-up at the House of Sewing Machines in Vancouver, WA. Overall the experience was great. The person who took in my machine failed to tell me that they were a week out on repairs. But when I phoned in to ask for an estimate, the employee was polite and explained it would be a week because they were swamped.
The tech who looked over my Viking called to let me know that nothing was seriously wrong with my machine as I had feared but that a tune-up would be a good idea. He didn't try to sell me anything extra.
I picked up my machine two days later and the tech took the time to answer all of my questions. He was a wealth of knowledge and didn't mind explaining some of the workings of my Sewing machine.
Pros: Helpful. Knowledgable.
Cons: A little difficult to locate.