The Nike Fuel doesn't measure sleep, and only measure calorie burning, steps and time spent on the move. I"ve been going to the reviews quite extensive because I wanted to buy one, but they are not so good and the device was marked not so accuratly but a nice gadget, it is also the first version. AND it also cost $149, remember we discussed it in SF. And I'm Nike fan but didn't buy it.
Lark life is brand new and not on the market yet, but I presume they have integrated their silent wake wristband in there, the measuring of sleep is based on moverments like Body Media, only Body Media have put alreadu 11 years of research in this and works with sensors that measure a lot of details, and therefor I think it is more reliable, we can check wen Lark Life is available to compare the two. Also here price range is $149
So far my comments!
Christel