What are some alternatives?
When comparing Songs2See and Yousician, you can also consider the following products
Flowkey - The easiest way to learn piano with your iPhone or iPad
Simply Piano - Fast and fun way to learn piano
Pianu - Learn to play the piano in your browser.
Playground Sessions - Online piano learning game.
TuxGuitar - A Multitrack tablature editor and player.
Synthesia - A fun way to learn how to play the piano.