What are some alternatives?
When comparing Jameasy for Violin and Songs2See, you can also consider the following products
Simply Piano - Fast and fun way to learn piano
Flowkey - The easiest way to learn piano with your iPhone or iPad
Yousician - An interactive guitar-learning app.
Pianu - Learn to play the piano in your browser.
Playground Sessions - Online piano learning game.
alphaTab - alphaTab is a cross platform music notation and guitar tablature rendering library.