Pros
The general work environment is livable. The slightly out-dated attitude towards it's employees isn't. A somewhat flexible work schedule is a plus. Sonic's Christmas (sorry, 'holiday') party is pretty good. As a first job, or more importantly, a stepping-stone job, Sonic can be useful for gaining some work experience.
Cons
Poor pay. Zero training. A total lack of an inherent, quality team environment is a major problem. I'm not sure the attitude of the sales managers would be tolerated in any other large corporations. Sonic's products and training is possibly amongst the poorest in the industry. Placing a few amusement machines in the break room does not constitute working in a "cool place" - certainly in light of the sub-standard pay, and (more importantly), the almost non-existant health benefits. Hindsight is a great thing, but I would have opted out of the health insurance that Sonic offers and chosen my own else where. In addition to the above (accurate) points, it has to be said that the bonuses offered by this company are also uninspiring.