I enjoy this app and find it helps develop pitch sensitivity. Recent updates have made it more enjoyable because there is less chance of missing due to impulsively hitting the wrong button, and you can also tell how many times you have missed (the previous version required you to track misses in your head).
My one complaint is that you cant save your personal best for improvement purposes.
All in all it is a great app, and fun to challenge friends with.
Pipingsongs about InTune – Tuning Practice