Ive really enjoyed using this app, I even paid to upgrade it! Totally worth every penny, and I really like the order they introduce new characters.
The one issue I have noticed, though, is that when Im using the "Review All" feature, two of the options are always あ and き plus very often と. This takes all the challenge out of the process when the answer will always be the symbol that changed. I also wish that they would make the review feature longer, so that it would always include every character form every lesson you have completed. Right now it is just a hand full.
Still an overall spectacular tool. I would absolutely recommend it and I hope that an update might come along to improve my one nitpick.
Drwatsonguy about Learn Japanese!! - Hiragana, v1.1.10