There is no real right answer for this question, but a few decent guidelines you could consider are...

1. How long has the company been in business? The longer it's been around, the more likely they are doing something right.

2. How big is the company? Huge companies tend to have far less personal service and be far more difficult to resolve problems with.

3. BBB is a great place to check reviews, but yelp and similar sites can be a great resource as well.

4. How do they bill? Some consumers scoff at the idea of a preset labor price to do a job, but it benefits you as well! If the technician completes the job faster than average, the company gets a little extra. What you pay for here is the technicians knowledge and experience. The opposite is true if the technician takes forever to get it done. You pay the same price either way instead of paying for the technician to learn on the job.

5. Backyard Billy's appliance repair and the like may are ones to steer clear of. A legitimate business with insurance is the way to go.

Hope these help!