While the Garmin Vivofit and Vivosmart can track sleep (and even better that the Vivosmart has a silent alarm), I'd love to see a feature similar to the Sleep Cycle app in iOS and some of the Samsung software where you can set a desired wake time and, using the sleep tracker, knows when is best to wake you (i.e. at your most awake already moment).
This is similar to the Leaf sleep tracker. Essentially a smart way to wake up silently using the silent alarm but at the time that makes you feel the most refresh.
