The training program is extremely solid. The gradual build up and variety can turn any non-runner into a runner. I spent my whole life playing team sports and swimming and always, always hated running just for runnings sake. Now that I work absurd hours every week and dont have a university gym or team sports conveniently available to me, running is the only affordable way to keep myself in shape. This program has helped me learn to set goals and enjoy working towards them.
As for the app itself- there are a few bugs/poor design choices. You have to lock the phone WITHIN the app (lock icon in top left) in order to continue to receive the voice commands over the music and see the timer. Even then, sometimes the voice doesnt come through for some reason. If you just leave the app up and allow the phone to lock itself, youll only receive text notifications of the intervals (so unless youve set your phone in front of you on a treadmill, you wont know whats going on.) It took me a few runs to figure this out- it wasnt clearly stated anywhere in the app.
Also, the app allows you to enter your distance and calculates your pace for you, but it includes your warm up and cool down in the calculation! So even if you ran a 8 min/mile during the actual run, your 15 min/mile warm up and cool down will skew the apps calculation and your pace within the app will be recorded as something like 10:40 min/mile. Theres no way to edit this as far as I can tell, so even though you can still compare one "pace" to another in the app, they arent actually reflecting your real run pace. Ive taken to calculating my pace using the treadmill stats and just writing them down separate from the app. If I remember to check the distance at the start and end of my run… Boo.