It is nice to measure oxygen in blood while sleeping
This is my second Sleepon. The app has changed since my last one, so I'm still getting used to it. I use it mostly to track my sleep apnea. That seems to be pretty accurate. So overall I'm happy with it.
Not intended to be an Oura ring competitor. That's good because the price is reasonable and there's no subscription. It looks odd and you wear it facing inwards while sleeping. It's more like a medical device than a fashion statement. You get heart rate, HRV, SPO2 and ODI, which is a measure of sleep apnea based on oxygen level averages rather than obstructive breathing events.
I'm skeptical of the accuracy of the sleep stage analysis since it's consistently too optimistic about how quickly I fell asleep. Also, detected deep sleep duration seems shorter than with other devices I've tried. I think you really need EEG to accurately determine this.
My main interest is checking my heart rate and monitoring my sleep apnea. I wish it had a microphone to attempt to detect irregular breathing patterns. It seems like this would be possible with something in close contact with the body, perhaps using AI to pick up what would be a faint breathing rhythm through skin and bone conduction.
I've only been able to get the blood glucose reading to work once, and I can't comment on the accuracy.
So comfortable to wear and the data produced is very accurate. I thoroughly recommend the Sleepon.