The app (on iPhone 5) finds my Bluetooth heart rate monitor (Mio Link) and my Pebble fine, but it only works for about a minute or two at a time. After a few minutes the heart rate (and elapsed time/calories display) stop updating on the Pebble (there is, annoyingly, no indication that something is wrong other than the fact that the number stops changing), and if I then unlock the phone I see that heart rate is no longer being updated in the app and the red heart has disappeared, although elapsed time is still updating on the phone (but not the Pebble). The only way to get heart rate back is to force-quit the app and restart it, at which point it will work for a few minutes, then freeze again. Rinse, repeat.
At this point I feel like Ive paid $2.99 for an app that doesnt effectively do the main thing it is supposed to do (receive heart rate information and display it on the Pebble). Developer has been entirely unresponsive - submitted a bug report over a week ago and followed up twice, developer never replied.
I guess i basically just threw $2.99 into the garbage.