Overall Good except sleep
I wear a Colmi Ring and a Fitbit. Steps, heart rate, etc overall track very similar. Using the ring because after buying Fitbit discovered it does not sync with Apple Health. Only really terrible feature is sleep tracking. Measure sleep after waking up for up to an hour. Also if you wake up in the middle of the night it will not notice. When I compare with my Fitbit that measures sleep very well, I have on average 30 to 60 minutes less sleep each night than what the ring measures. Not great also is rest or stress level. Very different values to my Fitbit, and I can feel that my Fitbit is much more accurate in detecting if I trained to much and need rest or if I am stressed overall. So if you goal is tracking steps and heart rate, go with this app and ring, for anything else you will be disappointed.