Gallivanting Gal runs a travel channel, and for the last month she's been trying to learn piano with Yousician. She's also been chronicling her experience, which is an excellent way to see if this practice app is practical. Here is her 30th day with the app.
Learning piano with Yousician, Day 30. I'm butchering Clementi's Arietta!
App I'm using:
Yousician app (iPad)