While some bounty hunters lay more emphasis on the community members of the project. I tend to look at the technical aspect of the Whitepaper, website structure and team because I have seen a lot of projects with large communities failed.
For me the best criteria would be to look at the project itself, a project which is planning to stay for a long time will most likely pay out the rewards for the bounty since they do not want unpaid bounties hindering their success in the market. Also I think that the bounty manager that is handling the bounty is also a big part as some are known to partner with scam projects.