I also switched to the sport one and I like it because I sweat a lot and use it while swimming and it dries quickly. But if I don’t wear it uncomfortably tight while sleeping it gets looser probably because I move a lot while sleeping. One thing I noticed is that the biggest drops in measured o2 levels happen while I wake up to go to the bathroom. Normally it only measures while your wrist is flat and the watch is facing up but it is probably not able to detect it that quickly.