Bought this ~2 months ago and have had 3+ support calls relating to not pairing, pairing then dropping quickly, pairing then reading zero, then reading intermittently, then turning into a random number generator with HR swings of 2-30+ bpm while doing steady state intervals. Garmin support was good at attempting to troubleshoot these and finally warrantied the device. Hopefully the next one is better.
The pairing process with my Garmin Forerunner 55 is a pain in the butt, I still can’t get it to work. It paired fine with my Edge 540 though and works fine there. I’ll probably return it and get a Polar.