They will get their work out of you. You will sweat until your whole shirt is wet. It's dark, dusty, messy but you're not alone most of the time. At least at the beginning they have a good trainer help you but eventually it turns to managers. Managers are the worst because even though they have been in your spot they still want you to drop everything and let your belt back up just to sign some papers at the other end of the building and trust me they will for your first month. Your coworkers will also hate you for a little bit as you're the new guy and they need to not only compensate for your slowness but also deal with any messes (eg box opening and spilling or a wall of boxes falling on you). One amazing thing though is this job can replace your gym membership.
A lot of people are nice and the pay is decent for them hiring anyone in the door way.
Some bad apples and lots of lifting