It's also an order of magnitude more accurate (source: testing my Polar H7 and my Moto 360) Current optical HRMs seem to peak out in intense activity, which is exactly when they're most useful.
The whole bunch seem good for general fitness, but not for athletic performance. For that a chest band still can't be beat.
And this, to me, makes them almost useless. That said, there are optical HRMs that are accurate and aimed at athletes, but ... they're aimed at athletes. Fitbit/Jawbone/etc aren't.
The whole bunch seem good for general fitness, but not for athletic performance. For that a chest band still can't be beat.