Pros
Good workout, great insurance, wages automatically increase every 6 months. The longer you're there, the better the job is. Union gives you job security, can pretty much do anything short or stealing and completely stop showing up and you still won't be fired. Health benefits are amazing, only a $10 copayment and free prescriptions to most medicines.
Cons
Constantly working; lifting and moving boxes. Could be working as fast as you can but your supervisors will still come up and say you're not moving fast enough. No air conditioning so the building literally becomes a "sweat shop" in the summer months. No matter how long you're there, you'll only get ONE ten minute break, even if you've been working hard for 6 hours. Must join the union and union dues take money out of your already small paycheck. Very dirty, very dusty, you WILL be blowing out big black boogers out your nose at the end of every day. After you've done it for a while, it becomes mindless work, and you can't use any music listening devices or cell phones to keep your mind occupied. Some of your other coworkers might be lazy and you have to pick up their slack. If you work hard and you're good a what you do, they place you with someone that works hard too, making your job extra hard because you're forced to keep up with the flow. No ones cares about anybody but themselves. Sure you can help the people around you, but unless you think about yourself first, the place will eat you alive. There are multiple entities (union, united way, drive,etc) that would like you to donate even more money out of your already small paycheck.