Not bad but a few things are missing
I have the App installed on an iPhone 6 with iOS 10.3. The App for itself is working but it won't sync my heart rate data with Apple Health, which is pretty annoying because the internal view of the heart rate is very bad. I hope there will be an Update which removes this bug and will probably bring a better view of the heart rate. #UPDATE: They have updated the app. The synchronization with Apple Health is now working.