The main value prop over the Apple Watch and current Android wear appears to be the battery life. They're advertising over 7 days on a charge, which is certainly better than whatever the Apple Watch will be in terms of battery life. I just worry about the market for apps after the introduction of apple's watch around the same time.
Actually, they're saying "up to" 7 days which is obnoxious because that could mean anything.
You can't really even have a "under normal use" battery life claim. My Pebble lasts between 4-5 days depending on app usage. Other have theirs lasting 2-3 days. My personal iPhone sometimes needs to be recharged in the middle of the day. My work iPhone gets charged once every three days.
"Up to 7 days" is the most meaningful number they could put there, because it shows you what to expect while using it as a watch. Everything else is up to you.