Pros
Good hours and management are nice as long as you are a good worker and keep busy. Be willing to help out wherever possible and they appreciate you. Some metros have better management than others. Schedule is usually flexible and you get major holidays off since the store is closed at a reasonable hour. Seniority is valuable so stay as long as you can, the longer you are there the more flexible they are with everything. Opportunities to work in other departments/more hours as well as managing departments after a number of years working there.
Cons
Some employees with high seniority think they are above you or are your boss, try not to listen to them but respect them. Workplace drama at least at my metro is always happening, sometimes leads to unprofessionalism. Sometimes hours can fluctuate. Union dues are a pain since they take from your pay. Customers are sometimes annoying but you find that everywhere. No discounts on food or groceries which sucks.