I can not think of any manager which I can call "the best." I've had bad experiences with bounties before and I've just came back. Probably I'd choose myself as the best manager because I have managed my work while doing bounties but I do not mean the best bounty manager because I never happen to become one.
But the question is all about those bounty managers. Yes you can be the best manager on your own depending on how you are good in managing your works. But when it comes to bounty managing, things are becoming different. You have to manage a lot of participants that are sending their works and you need to verify and check them from time to time.