It's a good review with some great pics of the device. I've owned both the WakeMate (OK, so it's not totally analogous, but I hated it besides) and the Fitbit (loved it, but recently lost it), and am not too sure how I feel about the UP. (For one thing, the name is terrible, no?)
I think my biggest problem with the device (having not used it yet) is that it's a bracelet. I always wear a mechanical watch on my left wrist and wouldn't dare let anything bump against it, and have no desire to also wear something on my right wrist. Moreover, I suspect it wouldn't flow perfectly around my wrist (from what I can gather it's not completely "moldable"), which would bother me to no end, not to mention that I don't like the idea of the rubber constantly tugging at my arm hair.