I've seen both sides. The town I went to college in was heavily unionized. The majority of them were fine.

We once needed to hang a network rack in our building. It was on the unions work list for 6 months. We finally just did it, a grievance was filed, and the company was fined for having a non-union person do a union job.

This was sadly the norm at that job. But it wasn't anything too exciting - nice guys, too much work to do, company wouldn't get more of them.