One drawback was that in the teach-me mode, we didn't see all of the examples of compound kanji words that the reference mode gave us. (A kanji can have different readings and, depending on the character or characters it is combined with, different meanings.) App creator Rory Prior says he is considering adding a vocabulary-training feature to the teach-me mode to address that.
Although its minimal text is drier in tone than Human Japanese, we loved the app's thoroughness (it covers 2, 230 characters) and flexibility, allowing us to use it either as a kanji tutor or as a reference tool.