I am a little late to the conversation but here is my two cents for anyone who reads this in the future.
I chose to join PKP for my own personal amusement. In addition, I joined while already in graduate school and I was wanting a new MacBook. PKP boasts Apple discounts for their members. I was more than disappointed when I learned that Apple only gives PKP discounts on random items; none of which, at least at the time, included MacBooks. As I investigated other "discounts" offered to members, I found that they were equally lame, for lack of a better term.
After my initial year, I chose to not renew my active membership because I was already a lifetime member (everyone who joins is) and the only benefit I saw to paying annual dues would be for access to apply for scholarships that I may or may not have won. Even then, I was already finished with school so that didn't apply to me. Their "career" advice is basically an online form that you complete, which is pretty much a super secret LinkedIn service, through which I was never contacted by a prospective employer.
They used to have their member directory online but now, they have converted it to a actual book that one may only have for a fee. Not long ago, they emailed me asking me to call and update my information for said book. I did so out of curiosity and spoke to someone I could barely understand who, I believe, was also trying to sell me something.
It was a fun honor to wear PKP garb at graduation and I sometimes enjoy the bragging rights. I do put it on my resume, but I do not think it has ever helped or hindered my applications.
I'd join again, but I'd never pay money to keep my membership "active." It benefits me in no way.