And like I said, there's up and downsides, and it really depends on what you want out of your career. Some people want the 9-5 clock-in-clock-out with well-defined rules and tasks, scheduled raises and all that, so they can focus on their real life. Others actually like the work they do, and are comfortable working hard to get four promotions in a year and "messiah" treatment from management. I'm sure there are bad non-union employers as you mentioned, but honestly in startup-land you're a lot more likely to have experiences like I described than otherwise.

>unlimited PTO

This, exactly this, is the problem with people in the union-mindset. "Oh it's unlimited, that means we don't need to work at all, right?" It means you have a certain amount of accountability and responsibility: "Hey, we just finished project X so I'm going to take Fri+Mon off to go camping" is a regular thing, without having to book your vacation dates a year in advance or deduct quarter-hours from your various "PTO banks", or even have to document it anywhere. It means the company trusts you to do the right thing. You're not going to see that in a union shop where you constantly have an adversarial relationship with your management.