Pros
You get to learn a lot of different things and sometimes even have the opportunity to acquire your notary public certification free of charge depending on your location, this is a great place to work if you like working with customers and love interacting with people. You're always learning new things for quite a while because the actual job doesn't fully entail what you do. You'll do anything from notarizations, to shippings, to even laminations. Usually pretty flexible schedule, you can catch a pretty good job if you call a UPS store during wintertime, thats when it gets the craziest and where you are most likely to get a job to lock down when it slows down in the later months.
Cons
The only cons are the customers and amazon returns. Depending on your location there might not be as many amazon returns but sometimes it doesn't get old and even frustrating the amount amazon returns you get. The customers do get mad quickly and don't care about treating you badly, your just another employee and UPS to them and it YOUR fault they had issues with shipping when in reality its not the case.