My experience with them is mixed. I’ve had a couple of theirs and they’ve been markedly inaccurate in some categories. For example, reporting I was not in bed when I actually was, or vice verse on other nights. As a result, the sleep hours were off. I still love it for the temperature control (set to manual, not their ‘auto’ algorithms), but if it can’t reliably report something as simple as whether I’m in or out of bed, then accurately judging sleep stages should be even less likely.

My oura ring has been far more helpful in identifying patterns leading to less quality sleep. For example , by highlighting elevated resting heart rates and asking me if I ate later that night, consumed spicy foods or alcohol, etc. That said, it’s not terribly durable. After a couple years it refused to accept firmware updates. Then a few weeks ago (after maybe 3 years of use) it stopped connecting to the app altogether and support tickets are going unanswered. This is greatly disappointing but I may spring for a replacement anyway because of how helpful it’s been in correlating lifestyle choices to sleep parameters (& quite consistently so).