Pros
Every day, you get one free meal. Employees also get 50% off all food at their store (you must order inside, not through drive thru). The hours are very flexible. I've gone from working full time in the summer, only every other weekend during school, and back to full time once school let out. I started a year ago when I turned 18. It's a very fast paced job, but the tasks are simple. You learn to appreciate certain things, and it's good place to start off as a young kid.
Cons
Of course, the employees (for the most part) aren't the brightest of folks. Some of the managers aren't very well qualified. Rules aren't set in place very well, and you WILL get yelled at - by coworkers and customers. When you're faced with upset/rude customers, you need to learn to not have it affect you. You come home smelling like fry grease, and your feet will hurt from being up and about all day. You're supposed to get a break every day depending on how many hours your shift is, but sometimes you don't get one. Sometimes, business will get incredibly busy, and everyone gets frustrated. You just have to know how to keep it rolling.