No need for a separate stroke coach!
Great for on the water feedback as it entirely replaces a stroke coach at a fraction of the price. The rates and speed data seems right on. The visibility of the phone screen is great, so long as you set up the phone in boat correctly with an appropriate waterproof case. It is a bit frustrating as it seems the recorded data is broken down by stroke, only. I wish it was able to be toggled to by piece or by 500m to allow a higher level of data review. For this reason, I usually defer to the recordings on my Garmin instead of in the app for post-practice reviews.