I have some kind of mixed feelings about airdrops. Why? Basically I have had luck with some of them (BAT, stellar, Obyte - formely Byteball, LOCtrip - ERC20), but other are just waste of time especially the bast majority of ERC20 tokens are just scam, they just want to get some free advertisement from the people tryng to earn some free coins of their distributions and in the end they don't give you a penny!