Basis Peak review: This is the band to buy if you obsess over heart-rate and sleep tracking

The Basis Peak is a vast improvement over the Basis B1, that oh-so-promising but still quite imperfect activity-tracking wristband from early 2013. The Peak is more stylish than the B1, has a better display than the B1, and is easier to use than the B1.  But best of all, the new $200 Basis Peak has a