More than just a book turned into an app, The Jungle Book app is interactive, including a narrator (British, naturally), music, and mini games like jigsaw puzzles and a coloring book. The coloring book feature could be an app on its own.
You can 'personalize' the app by adding a photo and name to the virtual cover. I'd like to see more personalization within the app, but it's a start, and should appeal to kids.
The Jungle Book app leverages the original film's artwork and uses a lot of panning and zooming to simulate the look and feel of the original animation.
I love when old meets new, and when Disney originally adapted the original story as a film, that was one such example and now they've done it again, in time for my kids to experience the story in a modern way.