Pros: great benefits, good hours
Cons: management can be lousy depending on location, you deal with a lot of problems
Costco can be a great place to work, provided the management is good. On more than one occasion employees would have to shout at the top of their lungs to get a supervisor's attention. Managers have come and gone, usually leaving some mess in their wake.
Understaffed at times, leaving cashiers to push carts instead of having a reliable cart crew.
Benefits are great. Always guaranteed good hours, but you work hard during those shifts. That can be good or bad, depending on the day.