unions are hit or miss, just like working conditions without them.
my last job was for a pretty big cable company in a call center with no union. they paid well and offered a nice benefit package but the job was crazy stressful and they shat upon employees hard and had impossible policies to follow and constantly fired the best employees that were there for 15+ years over total bullshit, threatened people all the time, the whole deal. they told people flat out in orientation that the system was designed to be impossible and make people fail. SIX MONTHS of notice for a day off, even unpaid, was denied, and they wouldn't cut you a check for your accrued time that you couldn't use and they capped the amount of time you could accrue. they would make us do work for other departments with no compensation but full liability. the list goes on. thank god for OSHA because the place was full of mold and decrepit smelly furniture until someone ratted, and a month later that person was never to be seen again. every day i feared someone was going to finally flip their shit and shoot the place up, but the pay was good and i had bills and was busting my ass to get into a better department (fat chance as i eventually found out.) draconian workplaces are alive and well, i assure you.
every time someone started some kind of union chatter or if any union reps started talking to employees outside the building the company would unleash a whole load of scary propaganda pamphlets and meetings and make threats to scare everyone out of trying to get a union. i made it 3 years at that place and i swear to god i'll never recover from it.
on the other side of the coin i know a few people who work for a large local hospital that has had a union for the "other employees" (not nurses but care aides, secretaries, housekeeping, etc.) for about 15 years now. they never really "needed" one as they were treated ok to begin with, and the union they got only cares about management. so now they get their raises every year but they get shit on by management who is completely protected. the place is a madhouse behind the scenes with everyone at each other's throats because management is basically exempt from any liability and the reps don't do shit for the peon employees. under the old system the managers would be held accountable for lapses in duties and grievances would be addressed, but no more. management just makes up rules on the spot and does what they please and punishes people for "crying to the union" and gets away with it. everyone i know who was there before the union says it was much better before, and for this privilege they must pay.
so it can suck either way, but the place i worked at should be on the fucking news. i can't imagine how a union would possibly make that hellhole any worse.