I wouldn't be interested in this product personally, as wrist-based GPS is a must have for me. But the UA HealthBox could be a great "starter kit" gift for someone trying to get their health on track. This review by AP's Anick Jesdanun delineates the many drawbacks of the device -- a higher cost than buying individual hardware separately, a high pace required to activate the running measurement. DC Rainmaker also gives a more in-depth review that's pretty positive, but comes out in the same place. The Verge finds it not only too expensive, but a little unreliable. For now, the price should be a deal killer for most buyers.
Since the devices are manufactured by HTC, I'd have some confidence in build quality. And the extra metrics -- and the dumbing down of exercise info (red and green lights to indicate effort, easier entering of meals as light or heavy) -- are very helpful for beginners, and I bet would improve compliance. Most people are already suffering from information overload, and this could help make sure data is used judiciously to create regular exercisers rather than turn people off. If they cut the price closer to $300 (why wouldn't they want to get people living inside the UA ecosystem -- they are also coming out with "smart" shoes Speedform Gemini 2s as well - also reviewed by DC Rainmaker of course) and iron out some of the kinks, they could be on to something good for the under-exercised masses.