Love this physical tuner, app ok...

TC Electronics-- please update this app! You havent touched it since 2010!!
This app is pretty good, but its not nearly as sensitive to low volumes as other tuning apps. I constantly have trouble with the high E string. I have to literally get the tuner right next to my acoustic to make that string work. Other than that, its a solid tuner.

wildchuk about PolyTune, v1.1.0