If you’re all about the fast money, focus on programs that offer cash payouts. If you’re patient, look for programs that let you earn points and exchange them for gift cards or other rewards. It’ll take a bit longer, but you’ll earn more for the same effort.
If you’re pressed for time, look for programs that pay you just for surfing the web or running a mobile app. You won’t make much, but it’s hard to complain about making a bit of extra spending money without much extra effort.
In the end, which programs you join is completely up to you. It really depends on what you’re willing to do and how you hope to get paid for it.