Pros
There are a lot of good, hard-working people from diverse backgrounds. These people are the true santa claus and his elves. Online shopping is huge today, and these are the people making it work. A lot of instances of good teamwork. Not everyone but a lot of people try to help each other.
Cons
Package handlers perform hard physical labor, often without much appreciation. Workers are beating the hell out of their bodies to support the economy. There is no climate control in most of these facilities, and in the summertime you will truly suffer. The tractor trailers bake in the summer heat, so the "feels like" temperature could be well over 100 degrees. During the summer my facility had heat exhaustion cases every day, sometimes several per shift... Supervisor roles can vary - some just stand around while people work and give orders. Supervisors in understaffed areas are doing the physical work themselves just to keep their work area afloat. Union workers get fantastic health insurance and some protection from unfair treatment. Supervisors are not in the union, so you need to balance the pay increase with the loss of union insurance and protection... During peak season (Black Friday - Christmas), we work much longer hours and the physical intensity and mental stress is much more severe. A lot of workers are at the end of their rope during peak season, just fighting to survive the tsunami of packages flooding the facility.