JRO26 wrote a wonderful and complete review on the site: ItPaystolearn.com Therefore I will not go into further detail. I only wanted to say it is sooo much fun to take the quizzes. The questions on level 1 are relatively easy but as you progress through the other levels the difficulty increases. This is an intellectual challenge.
I joined only a week ago and have been having so much fun I suggest you try it for yourself. Signing up is very easy and the questions are certainly doable. Don’t be afraid to try.. you have nothing to lose and everything to gain.
Have fun!
Claire