What are some alternatives?
When comparing Pianu and Yousician, you can also consider the following products
Synthesia - A fun way to learn how to play the piano.
Simply Piano - Fast and fun way to learn piano
Flowkey - The easiest way to learn piano with your iPhone or iPad
TuxGuitar - A Multitrack tablature editor and player.
Playground Sessions - Online piano learning game.
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.