> Looking at my teams, the amount of PTO people take has almost no correlation to whether they have unlimited PTO or a set number of days.

If the number of PTO days taken is the same between the groups, isn't it CLEARLY superior from an employee perspective to have a set amount? That way, you get paid out if you leave or are fired.

I know quite a few people who use their PTO as a sort of emergency fund if they are laid off... they will at least get paid that amount to hold them over until the next job.