The interface of this app does look nice but it is lacking two major functions and is only a mediocre app without them.
1. Interval training apps must be able to run simultaneously with music streaming services such as Spotify. The app does allow you to sync workouts with music already loaded on your phone, but this leaves out thousands and thousands of users who pull their music from other streaming services as Spotify, which pauses automatically when in use with this app
2. The app does not allow you to set rest periods in between your exercises. This causes many of us to set up our workouts in an impractical, unrealistic way
Travelkey about Intervals Pro - HIIT Timer