Avantages
Flexible hours and scheduling; management will (usually) work around your schedule, whether you're in school, have a second job, or just want to work a strict part time. Half off and free food benefits. You can get half off on most food items (stipulations vary) and you can get free food if you work a double shift or if you train someone. Cooks typically get one free meal when they work. Promotion to management is usually done in-house. So if you stick around long enough, are half competent, and show a desire to become a shift manager, chances are you'll get the chance within a year or two.
Inconvénients
High turnover. People come and go like clockwork. Minimal health benefits for full-time employees. No holiday pay. Very little incentive to keep good employees. A store can be good or bad depending on one major thing: the management team. I've worked in the same store for more than five years and the biggest factor that decided good days from bad was the management staff.