5 stars: I like this app. It's resulted in me getting quite a few paid apps, game microtransactions, and e-books basically for free, or at least the accumulated effort of taking a 20-second survey every once in a while. If you're alright with admitting to yourself that your location is being tracked (which it most likely is regardless), at least you can make a little virtual pocket change as a result.
5 stars: Surveys take like ten seconds to complete and give me a little spending money for the play store as a fun treat every now and again. I would not otherwise spend money on apps outside rare circumstances so I have a good time with it. Because I am not aiming to buy something specifically, the money builds faster than I might have expected.
4 stars: Answer short questions and get a tiny bit of money for it..not sure how the algorithm works but I rarely get these come up..if you get these a couple times a week it's worth it since it literally takes less than 10 seconds to complete but if you get them once a month or less then don't waste your time. least I was paid $0.10..highest was $0.98.
3 stars: super nice way to make a little bit for gaming. However the frequency of surveys is a little annoying when it's been a while waiting for a survey. if there were just a selection of surveys you could take all at once I think would be a lot better way of going about it. And the last point for me is asking for a receipt for places I've shopped at that's just a bit sketc...