Its true that its risky to work with most of newbie manager cause there is no guarantee they'll pay your reward.but can't say that well reputed manager'r project would succesufull.its up to you and your analysis.for example: bountydetective and small rabbit, both were newbie manager.but good bounty manager, in my opinion.because of their well work, they gain people trust & merit and get promoted to member rank now.so all newbie aren't scammer
The bounty manager also depends on the project they manage. if many are scams, it becomes an indicator that the bounty is not professional in choosing a project. because we all work with the rules that we set but the bounty is not good. I currently join Small Rabbit and am currently experiencing payment delays due to high transaction fees on ethereum