I agree with the reviewers scepticism towards the usefulness of the statistics, but I am interested in buying this to make my mornings better, not analyzing my sleeping patterns.
Perhaps this review was just a fluke. And yes, it's a V1 - at least as far as feedback from the real world goes. But to me, a lot of the things that surprised him (that having a partner would influence the readings negatively, for instance) also surprised me. I would be hesitant to give something like this as a gift to a "mainstream" person (a "normie", if you will) right now - just because I would worry that WakeMate's manual/interface/whatever isn't yet ready to help my friend through any misconceptions they might have.
It rings very, very softly (user configurable for how long), and gradually ramps up it's volume.
This achieves the exact same objective of optimal wake time. If I'm sleeping soundly, then I don't wake up until it ramps up quite a lot, but if I'm already awake or just starting to wake up, I hear it quickly.