usually one man show.... Owner / Mechanic are generally the same person.... alot of stress to figure out issue of car, pricing of parts and services, suppliers.. and naggy customers who thinks they know more than mechanics.

Not sure if insurance companies use good service is a measure of making one workshop a panel....
think its more being honest in repairs / pricing at best.. to using the most cost efficient way to do repairs. hence i dont think being a panel is a good measure of quality.
Small workshop .. bad reviews...
big workshop.. also bad reviews
guess you will need to do your own research and go see the operations yourself.