While Oura’s readiness index is useful, I feel it’s less impactful than WHOOP’s “traffic light” system of red, yellow and green. More importantly, Oura doesn’t correlate lifestyle choices (tags) with sleep performance or readiness.  While I appreciate that correlation isn’t the same as causation, WHOOP’s ability to correlate behaviors (e.g., alcohol consumption) with sleep performance and recovery makes tweaking those behaviors and trying to improve one’s performance a fun exercise.