I’ve been using this tuner on my iPhone for about a year now. It’s a great, accurate and very cheap guitar tuner. I’ve tried other tuner apps, but they were not as accurate as this one. The free Gibson Learn & Master-app, which includes a chromatic tuner, is not usable because it is far from being accurate. I also tried another free app called Acoustic Guitar which again doesn’t work because you have to rely on your ears to tune your guitar.
In practice I’ve compared Tune Up to my standalone Boss TU12 guitar tuner. I use the TuneUp’s ‘needle’-display, which is much like the TU12′s display, and found the output to be the same: both are accurate, but the iPhone’s built-in microphone is much more sensitive than the TU12′s built-in mic, so it much easier to tune up an unplugged electric guitar with the TuneUp app. For the TU12 to get a good result you have to hit the (unplugged) string real hard, as for TuneUp, it immediately responds, so TuneUp output is quicker dispayed and it is also easier to tune because when your tone is sharp or flat it is shown in the display, as for instance ‘A#’ as the TU12 only shows a red triangle on the tight if the tone is sharp and a red triangle on the left if it’s flat. Another advantage for the TuneUp app over the TU12 is that if you forget to turn off the TU12, your 9V battery is sucked dry even when you put it aside.
The biggest disadvantage of the TuneUp-app is that for unplugged electric guitars it is quite unusable in noisy environments as it will pickup too many surround sounds. This is one of the main reasons why I’m not selling my TU12 as I rely on the ability to plug in the electric guitar directly into the tuner. Also, for adjusting the bridge-saddles I still rely on the TU12, with the guitar directly plugged in the TU12. But that’s because I still have not adjusted a guitars bridge setup using the iPhone-app. Maybe I will in the near future…
With Tune Up I can always tune a guitar everywhere I go, and now most of the time I can leave my good old ‘bulky’ Boss TU12 at home!