For a Junior member like you, signature campaign is still not a good way to earn bitcoin, the pay rate is really low. Even a Senior member like me still feel that, even that the signature campaign in which I take part is one of the best around. About time and effort, when you have lots of free time, yeah it's not much of a deal, just like a piece of cake, but there will be periods you are busy as fock, you will feel that posting for signature campaign is stressful. The bad thing is if you choose to stop momentarily, you may be kicked and have gaps in your post history and no signature campaign will accept you again with those gaps.
Unless you have multiple high rank accounts, but it's also mean more time and effort.
If you only have one account and think signature campaign is the best way to earn bitcoin, why don't create another account and do more instead of alternatives?