I'm not sure which bounty is a good one, but I think the bounty that has a lot of participants is good bounty.
Generosity is always different and depends on the number of participants and proportion of the ICO highlighted on the bounty. If you have a account with good rank, then the reward is very worthy. One company you can earn up to 3 ETH , but it is not bad money nowadays. In addition, you will receive a cryptocurrency, which may in the future cost much more.