Coming at it from a non-union position, I can say in our area the unions are corrupt, nepotist, criminal organizations but I've only dealt with the highway department (went to the hall for a while, but only family members got sent out) and the chemical workers union. Now I'm very happy the unions protect some employees, people who do try and do good work that I'd fear the company would take advantage of them without the union's protection, but the majority would use union rules to their benefit. Good example, I was sitting in the smoke break room one day and one union operator says to the other, "I told her if she kept coming into work drunk everyday and sleeping through her shift in the back they were going to fire her, but she didn't believe me". I have a lot of anecdotal evidence like that. Now, I only have experience with the unions around here so maybe things are different in other parts of the country, but I have a lot of personal experience locally with union corruption and strong-arming that makes me very much against what they stand for. I don't resent friends that work in the unions, sure all of them had parents/relatives that got them in, we just don't discuss it. But, please, I've actually seen some very strong cases of sloth and corruption so at the very least you cannot make a blanket statement that all unions are good. My experience is I have a much more stressful position, work harder, worked hard to put myself through school, yet make less than the union workers.
