Here's a head-scratcher: how can a fitness tracker accurately track your performance on an exercise bike? We're not up for suddenly moving the thing from wrist to ankle, thanks very much.
One of the few real casual-style devices to support ANT+ goodies is the Garmin Vivofit, because Garmin puts it into virtually all of its wearables. What we want to see is ANT+ and Bluetooth support in all trackers, as that means compatibility with smartphones and sensors alike.
