Pros
You'll get free things from time to time. Going through really unpleasant experiences together makes for long-lasting friendships with coworkers. Lots of turnover means you'll be able to pull in quite a few hours and get promoted to full-time pretty easily (all of my promotions happened that way).
Cons
Underpaid and overworked. I worked 1-2 hours off the clock every day as an assistant manager and manager. At my interview to become a manager I was both offered the job and it was heavily implied that if I didn't have the store back on track in 90 days I'd be fired. They will actively create a hostile work environment to get people to quit (so they don't have to pay unemployment). Gossip and backstabbing abound on all sides, but especially from District Managers and up. By the end of my 2 years with the company I was physically ill all day every day from stress. They expect you to have 100% availability and be on call all the time (no call/no shows are really common, for obvious reasons). Insane sales goals that you have no hope of hitting, and an upper management that really doesn't care about anyone who works at the company.