Re: GPS independence, good; battery life, weak; need for accuracy, overblown
The problem I have with wearables of this sort, whether from Microsoft, Apple, or Google, is that they're niche products with mass market pretensions. Smartphones make sense -- there's a benefit to having a small Internet-connected computer in your pocket. Watches that convey notifcations, are tied to smartphones, or independently offer communication and biometric data services make sense only to a subset of the smartphone audience, and probably not a very large subset.
Wearables like this show the tech industry acting like Hollywood -- we had a hit with the smartphone, now let's make it again as a wrist-mounted device.