PhD is useless if you wanna earn big bucks. It only matters BIG TIME in the academic field. Usually those who intend to pursue it do it because of two main reasons (1) you are in the academic line and you are gonna make it your career, not just merely as a job (2) your personal dream. I'll do it because of both. If I'm not teaching, I'll think twice whether to waste so much time pursuing it. Industrial/non academic work field - I guess prolly Masters is more than enough.

My verdict? Experience if you're in non academic field, PhD otherwise. But work first I would say as from that you'll know which specialization to pursue.