Pros
The employee discounts are incredibly good. 30% on top of any promotions (except 50%, and clearance0 everyday, and 45% once a month or so. You also get 50% off of everything for your first employee purchase. Hours are pretty flexible as well. The store I work at is understanding that a lot of their employees work two jobs or also attend school so they're very lenient with occasional availability changes. As long as you're on time, respectful towards customers, and do your job somewhat well- you'll never get fired.
Cons
There is no full-time employment unless you're a Sales Lead or Store Manager. A sales associate can look forward to one day getting 20-24 hours a week- but it'll take a while to get there. Being part time means no benefits. Sales Leads get benefits, but it takes a lot for an associate to make it to Sales Lead. Customers can be frustrating to deal with just like in any other retail environment- but the layout of Express stores doesn't help. Certain shirts require specific folds, packaging, etc. The men's side of Express usually has anywhere from 300-500 graphic t-shirts on the sales floor at once. This makes closing down the store a nuisance.