Vantaggi
As long as you show up every day and aren't too drunk, there is very little you can do to mess this job up. Learning the registers takes 10 minutes and after that you can pretty much do the job with your eyes closed. You get to work with people, mostly neighborhood regulars, so if you enjoy that sort of thing it's a big plus.
Svantaggi
They pay slightly more than minimum wage and do not give raises or promotions. They will do everything they can to avoid giving you your benefits and will cut your hours down as much as they can so that they can keep you as part-time. The management is largely unconcerned with the FOH staff and will neither help nor hinder you, which can be both a pro and a con. Basically, it's a good job if you're a student or need a few extra hours to make the rent, but don't expect to advance within the company or to be rewarded for doing a good job.