I've not used the platform, but I have seen quite a few threads discussing whether they are safe or not, personally I would just focus on here when it comes to finding bounties, there are plenty and you can get in contact with the bounty manager.

If you are you are looking for a new interesting bounty, Unitalent seems like a great one, they are a Swiss based blockchain high skilled freelancing platform (think of Fiver with people who are highly skilled professionals. Link is below and I hope this helps!