Great app, especially for review

You should look at this app as a great way to learn vocabulary and refresh your listening and grammar skills. It wont, however give you a great understanding of grammar or verb-ending rules. The best way to learn those remain text books, lecture, and conversation practice. This is also not an app thats going to teach a novice how to write kanji (or to read it rigorously)

Caveats aside, for basic 4 skills training, the software quality is very high. Because it is humble in its goals, its really good at what it does and should serve as a superior approach to most flash card apps (because multimedia is more engaging and illustrative).

For novices, Id recommend pairing this app with the Genki or Yookoso textbook series. For intermediate students, consider augmenting with the video lectures on Nihongo no Mori (YouTube)

J. Searls about iKnow!