Both of them are good to make money in crypto for free but it all depends of the project to say at least. I have been doing airdrop and bounties since 2016 and I must say that I earned decent money for past 6 years from it. My breakthrough was last year with civic airdrop that really gave me a big profit around $12k and that's all for free. That's why I never stop doing bounties and airdrop, who knows it might again another civic airdrop I will encounter this year.