I've worked the same role in union shops and non-union before. Non-union paid more and had less deadbeat co-workers to navigate around. Depends on your profession and skills, honestly. Probably a benefit for amazon pick and drop workers.
Really sucks at mixed union and non-union tech companies, though. At my current company programmers aren't even allowed to move our own computer between desks because only union people are allowed to do that, and getting the union people to do it will take over a week and be done at an inconvenient time interrupting work.