The decision to hold or sell a token gotten from bounty campaign depends on how good the project is.
If it is a very good project, it is better to hold the token but if it isn't that good, it is better to sell off and buy other tokens.
Even if a project is exceptionally good, there is no 100% guarantee that the coin will be successful in the future. That's why coins such as Monero are gong down and at the same time Ripple has been able to climb to the 3rd position.