I just check the app Bob. It looks great. Have just started using the app for GRE exam preparation and have started liking it already. I hope it will turn out good as I will go ahead with the GRE exam preparation.
You an check other apps also. Apart from that, if you carry tab or even a smart phones, you check the web version offered by various other companies. I have tried others also, However I am find gradestack quite good.