My uke tuner stopped working, so I looked at all "chromatic tuner" apps. This looked like the best bang for the buck, it costs less than the new battery my old tuner might need! Its FUN to use, and much better than the dedicated tuner it replaces. Works fine on the iPad with the iPad built-in mic, at 2x. The graphics arent as sharp as a dedicated HD app, but this purpose, who cares.
Syzygies about PitchBot - Smart Chromatic Tuner