If you check the proposition of time you invest to get one such bounty that can be profitable is not worth it. This is my personal opinion. Bounty are not my cup of tea and I would not suggest one to waste time on it.
I agree, last time I have seen successful bounty was mb8coin, I can't remember any other successful project for bounty hunter although I'm not up to date with the recent bounties. For getting a successful reward, one has to participate a lot of bounties and wait a lot of months.