Edward,
I can only speak from a sampling of one, so take what I say with a grain or pound of salt.
I am a niche consultant, not a professional project manager. However, I must manage client projects professionally. With that in mind, I found that studying for and obtaining my PMP has allowed me to better communicate with clients of all sizes and more so, clients that have Project Management Offices within the organization. When working with client's PMO, I can "speak their language" so we can both understand each other's needs and requirements in order to get the project done smoothly.
I had a professor once tell me, "no education of any kind is ever wasted." For me, obtaining the PMP designation falls under that. Certainly not wasted education.
Good luck in your decision.