unlimited is a scam, people tend to take fewer days when you tell them it is unlimited comparatively as when they have a fixed number of days. I know, I did the same. Now I take care of consuming my allowed PTO entirely and I take a lot more days off than before.
Living that now. Unlimited PTO sounds great, but the reality is that your days off ARE being tallied, and they WILL be used against you for the purposes of denying raises, lowering bonuses, or withholding promotions. It's up to you to police your own usage of it, because your managers will basically give you all the rope you'd like to hang yourself with.
My current job has unlimited PTO, but it’s not called unlimited. It’s called “discretionary” time off. And I think that’s an OK term for it. You don’t have a limit to your vacation/sick days, but you have to be a professional about it and not let things fall apart at work.
I’m fortunate in that we mostly work as a team and treat each other as human beings, even including the project manager and our direct management. So it can be alright at a good place. For example, we were asked our vacation plans for the quarter and I decided to add an extra day to a decent short break, and I gave myself a week long staycation next month.
But no limit also means no minimum, so of course the shittier places will use it to make things worse.