I'm not bounty hunter, so I can't answer from my own experience. But I think that both type of bounties have their own advantages. I see that people joining both type of bounties, so they probably don't see big diference. I think you should try yourself to see which one bounty is better for you.
Being a manager is far better than doing bounties, when in terms of work the manager has the easiest job and when it comes in payment the manager has the highest amount that will get.
Bounty manager job shouldn't be easy if he doing his job professional. It's not only about counting posts in Bitcointalk and social media in automated way. Bounty manager also should check quality of participants posts, remove multi accounts and other abusers and do other stuff. But unfortunately, there are not many bounty managers who are doing their job as they should.