But it never got great hardware (the 640XL was the best of the crop, considering price), the app situation was disappointing, though acceptable, and Microsoft never seemed to fully commit to and push it (just like Microsoft Band).
[1] http://www.dcrainmaker.com/2016/01/microsoft-band-review.htm...
To begin, from a 24×7 standpoint, the HR values presented are generally accurate when you open the page to view them from within the band. When it does this, it notes that the HR is ‘locked’. I see no issues when standing/sitting/casual walking/etc in this area, it matches other measurement devices here when viewing it at a moment in time. However, when looking at HR data over the course of the day, it’s largely useless (just like the Vivosmart HR), due to the low update rate.
It's got an amazing number of features, and as a casual user, that's not one that I was particularly interested in. The accepted wisdom seems to be that if you really want HR readings for fitness training, you want a chest strap....