I think what patio11 is doing with Starfighters.io is orders of magnitude better. Run developers through a gambit of supremely difficult tests via a fun CTF-type game and pair the best hackers with the highest enterprise bidder. Works not just for pentesters, but all devs really.
Also, I know where to get the best pentesters because they're listed on all the top companies' bug bounty pages. It's proof of skill I'm after, not some Gartner-esque gatekeeper telling me who's best because they've "background checked" them.
Give me a system more like StackOverflow or Starfighters where I can see the work. Not something subjective like eBay or Yelp, which can be easily gamed.