I tend to think that, overall, unions have been a good thing for US workers (all the current "rights" enjoyed by workers, such as vacations, weekends, overtime, and a finite work week were the result of union action; that they are being eroded is because of a political elite who feel that individual rights are trumped by corporate convenience). Of course, I currently believe that the one group of workers with the most powerful union is (US) corporate CEO's: their compensation is decided by boards that are under their influence, and usually consist of (shocker, this) other corporate CEO's.