Do not choose a shop based only on a convenient location. Look for a tidy, well-organized facility with vehicles in the parking lot equal in value to your own and modern equipment in the service bays. Ask if the shop usually handles your vehicle make and model or type of repair.
Some facilities specialize.
Look for signs of technician competence. Professionally run establishments will have a courteous, helpful staff. The manager, service writer or technician should be willing to answer your questions. Labor rates, fees for testing and diagnostic work, guarantees, methods of payment, etc., should be posted. Feel free to ask for the names of a few customers as references.