My Take
I do like this app. It's great for beginners. It helps to promote good practice skills and habits. It shows you the mistakes so that you can go back and fix what you got wrong. One of my critiques would be to add concert band and string instruments to the app as well.
How I Use It
I have not used this with students yet, however I have used this myself to practice piano. It's easy to follow along. You can pick the what level of difficulty you will like to start with. It shows you the notes that you got wrong. I would use this app for stations. Students would be able to work on their own if learning how to play piano or guitar or voice etc. This is also a tool that can be used for extra homework practice.