Why are they good? Because they ensure that employees are all paid, disciplined, scheduled and assigned duties the same - no favoritism or preferential treatment. And it takes a while to fire people. Why are they bad? See above. Then add to it that Management and Union Stewards and Leaders tend to antagonize each other, and that in a lot of ways (at least in places where unions like SEIU represent workers), individuals don't get recognized for going the "extra mile" in the job. I'll never work another Union job again if I have my way.