I think that depends on the bounty you would choose, for one, signature and social media campaigns in bounties pay the highest because they are allotted with the highest percentage ranging from 25% to 40% to the range of even 50% for some projects. Therefore, having that big of an allocation, it could be assumed that if such project would meet its desired investment quota, then it would surely get you a bigger return. Now on your question if some projects don't give whole payments, or worse, not pay at all whatever the case may be. Yes, there are. They are either scam projects or those that unfortunately didn't reach their quota, and is basically, a failed project. That's just one of the risk that people in it must carry, though. There is no guarantee in this market.