Pros- You get a nifty booklet in the mail that outlines Teamster corruption and tries to scare you into voting for liberals by using terms like "war on workers."
Cons- You eventually realize the company does whatever it wants and the union only cares about getting your dues. You also realize that you pay for union brass to get raises and take trips all over the country while you are forced to work overtime in semi-barbaric conditions, have your time allowance cut on a regular basis, get harassed and bullied, and an ever increasing workload. You will soon realize that the union forced a garbage contract upon you, as the company starts to transition to a workforce of essentially temp workers that get no real benefits, lower pay, and a 7 day work schedule. That's just the start of it.