I would have made this an editorial comment like I usually do with complaints about poll options but I think what I have to say has a large bearing on the discussion.
The poll falls into the trap of the excluded middle. The only real options in the poll are that either unions are good or bad. The truth is that they are both. Not only are there good unions and bad unions, but some unions are both good and bad to differing degrees.
Having a union doesn't automatically protect the rights of the workers. There are a tremendous number of unions that are either completely run by the company that they supposedly represent the workers at or are completely self-representative (meaning that the union represents itself, not the workers that belong to it). I'd name a few, but I think that might put me at risk for some bricks coming in through my windows. We need to keep in mind that unions can be (and have been and will be) abused and cause problems for both workers and corporations.
On the flip side, there are also a tremendous number of unions that do represent their workers. This is especially true in third-world countries that do not have as many labor laws as the US. We would also do well to bear in mind what working was like in the days before unions. If it wasn't for organized labor, I doubt I would have my well-paid non-union job with such nice benefits. If nothing else, the spectre of unionization helps keep companies a bit more honest in their relations with we grunts. If unions were entirely bad, true unions wouldn't be outlawed in totalitarian communist societies. Remember that it was a union movement, Solidarity, that brought down the totalitarian government in Poland.