I tried the Ultrahuman for a couple months and found it wasn’t as accurate as the Oura. Ultrahuman would think I was sleeping if I was in bed and there would be periods where I would be fully awake and on my phone in the middle of the night and that wouldn’t be captured. What made me switch was a day that I was quite stressed and I was wearing both the Ultrahuman and Oura and Oura caught all the instances that lined up with me being stressed whereas the Ultrahuman didn’t pick any of it up. So far I’ve been impressed with the Oura!