Pros
I worked for Tom Thumb for about 10 years on and off as I attended college from 2001-2011. The company had high standards of employee dress code, work ethic, and presentation. They demanded every ounce of strength and the general perspective was "If you can't do it, we'll find someone who will." My work ethic was built at Tom Thumb. The general pros are: customer service experience, tasks that are demanding and defining for a young person's work ethic, and the best pay and experience comes when you move from the front end into one of the fresh departments.
Cons
8 years later I was in a difficult spot and returned to work part time in the evenings for several months. This however was after an investment bought out both Tom Thumb and Albertson's. Since the buyout/merger, I noticed some of the very things which led to the failure and closing of so many Albertson's locations had now become a part of Tom Thumb's DNA. Dress code standards dropped. Work ethic and expectations dropped. Things simply seemed more relaxed which in a few ways was positive, but in all the ways that mattered and that made business successful, it was a serious detriment. The general perspective seemed to become, "We're just glad you showed up today." It seemed less important that someone was doing their job well and more important that a warm body was present. The general cons are pay, low standards, poor teamwork and low quality coworkers.