Good but not enough.

I downloaded to use with my apple watch, but it seems that when you have your phone locked, it simply stop working. (Syncing with the watch). Then you miss all the alerts.

So basically you need to have your phone unlocked in your pocket all the time to have your watch updating.

It also needs to give you the option to not auto start the next circle. So you can use for trainings where you have to move from one equipment to another.

Also it needs some help to understand how to make the workout more customizable.

Carlosnogu about Intervals Pro: HIIT Timer, v1.6