I am a professional flutist and teacher. I find this tuner very easy to use. The color changes from pink to green when notes are in tune. This makes it easy to check intonation out of the corner of my eye while reading music. And my students love watching the color change. It is very intuitive and even the youngest ones (7 years old) can understand how to tune very quickly and easily. This app also includes a tone generator which is very handy for practicing tuning by ear. And I love the fact that I can adjust the sensitivity of the tuner to be appropriate for the skill of the player.
The metronome is just so-so. But I have an excellent metronome app so I dont really care about that.
Flutist/teacher about Tunable – Tuner & Metronome