They’re both good Apps! I’d recommend downloading both and using both for a week to see which App is a better fit for you. You may find it easier to learn from one than the other.

In terms of study material, they’re both perfectly good. I have another GRE Vocabulary App to recommend to you: What are good apps for GRE vocabulary?

The [url="entrayn.com/galvanize/vocabapp/?referrer=utm_source%3DFBGroup"]Galvanize Vocabulary Builder App[/url] was designed by alumni of Stanford University and IIT-M, specifically to help students from all over the world boost their vocabulary for the GRE in the easiest, most fun way.

Download the Apps and see you for yourself which you find most fun to learn from!

You will be in good hands, regardless of the App you choose.
Free GRE practice Test: https://play.google.com/store/apps/details?id=com.entrayn.qbapp