Pros
Some of the pros is that you get access to all of the best deals in the store. The employees who you usually work with are pretty friendly. The job itself isn't too hard, it's pretty straightforward.
Cons
If it's a slow day you're going to be expected to be cleaning the whole store. Let's say you signed up to be a cashier, you're not only going to be doing cashier work, but you're also going to be working in the back, electronics and whatever position they want you to work in. You're also going to be critiqued on how many people you got to sign up for the rewards program or the credit card. If you're closing the shop and you're not under 18, depending on your store be expected to stay at least one hour later cleaning up the mess. If there isn't a holiday coming up the store's usually going to be understaffed so be prepared to be doing the job of 2 or 3 people.