Pros
The pay isnt bad, made about 40K the first year but worked between 50-55 hrs/week. It's fast paced and you have a definite opportunity to show off your selling chops if you so choose. The opportunity for advancement within the company is very real, and is based primarily on sales performance and customer retention. There are store managers in my district that earn $200,000+ a year (the ones that have figured out how to work the bonus structure). I think $80,000-$120,000 is more the average. It's also very rewarding helping people take care of their vehicles, and making an uncomfortable trip to the repair shop easier.
Cons
Working within the auto repair industry can be very challenging, physically and mentally. Many people will just assume you are a crook and a liar. You will interact with highly emotional people, and will need to ask for sales even when customers become upset. You will stand on your feet all day as well, running all over and being very active. 10-12 hr shifts are the norm.