Google Opinion rewards, is a rewarding program which credits you Google Play Credits each time when you complete any survey on this app.
You have to register and you will be notified every time a new survey is out and you just have to give your experience more precisely your opinion and that’s enough you will be credited instantly in form on play store credits.
All surveys are based only on Google’s various applications like Translator, Maps, Hangouts and so on.
Now whats really annoying thing of this reward program is you get quite a LESS number of surveys, which ultimately means less credits, consider mine experience I haven’t received any survey from one month(Refer to image I have uploaded) and in My view to get surveys frequently just use more and more google apps.
Summing up, I would say Its an just good rewarding app with simple concept, simple layout and simple user interface.