I had some limited business dealings with them that were super shady. Weird nepotism rules where people get their sons/nephews hired. Generally pay based on seniority not skill. Makes it really hard to fire bad actors or people bad at their job. (see teacher's union/police union) Leads to incredibly weird inefficiencies about who can do what. If unions were in software a dev couldn't update a Jira ticket except under very specific circumstances. Generally makes it harder to get a job.

If it just increased pay that'd be awesome, but it tends to have a lot of knock on effects. If the U.S. was completely unionized I think we'd all be poorer for it. I think there are better tools in the policy toolkit to make sure people who are struggling in the economy are taken care of.