Why choose? Try both - what would you like more - do that. In the bounty there is more responsibility - often you need to make reports - in airdrops it is easier.
With some members who don't care Airdops are profitable or not then do both if we don't lose any money on it.
I am joining a lot of airdrops last year but I decided to quit this year because I am having much issues regarding free tokens from airdrops.
I only prefer joining signature and other bounty campaigns in this forum because bounty campaigns are more profitable than airdrops and worth the wait.
While I spend more time, efforts and sacrifices but the most important is it's worth the wait because I am now holding good value altcoins that offers me a lot of opportunities.