There are 2 sides to every story. Most are probably familiar with Walmart's issues. i found this documentary to be enlightening:
http://www.pbs.org/wgbh/pages/frontline/shows/walmart/
I know people who've worked for Walmart, and NO ONE gets full time with benefits, hence the reason Virginia (I believe?) passed that insurance law targeted at Walmart. Walmart alone is a good reason for Unions.
ON THE OTHER HAND..
Unions CAN be detrimental to a business. I've had some personal interaction with UAW folks, and some of the highlights include:
slowness: If a lightbulb needs to be changed, they need an hour to get the lightbulb, 30 minutes to get to the socket, and an hour to get back- with a 15 minute "standard" break in between.
Arrogance: Many are cocky and they let you know it. They make a lot of money, and don't mind telling you exactly how much, and they let you know that you're not the boss of them (unprompted, no matter you attitude towards them) and that they will do their task "when they get around to it"
Laziness: I recall in one building I used to work at there was a certain older union person who would drive near the building I was in, which was part of a large complex, drive to the back out of sight, and proceed to sleep in his car-not for a short nap, but the entire afternoon-every single day. This went on for weeks and weeks- maybe longer but I finally moved to a different building- people in my building would comment and joke about it, because we could see him from our building, but security (and his boss I imagine) could not.
beaureaucratic: If a union member who's an engineer walks by and sees a pencil on the floor, and he picks it up, he gets yelled at, because according to the union rules, by doing that he is taking away the union janitor's job function. I was not allowed to carry anything heavier than a book by union rules because I was taking away a union members job- despite the fact that putting a union request in usually took days, if not weeks.
I don't mean to say that there are no hard working, committed union workers that do their jobs well, but there's a prevailing attitude of indifference and overconfidence-at least from what I've seen and heard. Many are supremely confident that it's nearly impossible to loose their jobs, and until the recent economic shift they were right in most cases. I have many other stories and examples, but I just wanted to make a point. This is the ugly side of unions that gets downplayed. I ecountered many of the above examples over the years.