So far, every company I've worked for has an "unlimited" PTO policy. In practice, it means that folks end up taking little/no PTO, or folks end up abusing the policy with extensive breaks for personal travel, etc. (I 100% support taking vacations and carving out time for personal projects and family stuff... I just kinda look askance at the idea of taking the equivalent of a 1-month sabbatical only 6 months after joining a company.)
What I'd love to see is Unlimited PTO with a mandatory minimum. Even for the most die-hard workaholics, having some time away from work stuff is important. For everyone else, a PTO mandate would make taking personal time just another part of their work responsibilities.