If the battery life doesn't suck (which I fear it does given the total lack of reference to it) and the "iPhone required" isn't as onerous as it seems, I might well wear one just for the easy 24/7* heart rate tracking. Granted the optical ones aren't as good as the HRM straps (as best I remember the dcrainmaker reviews) but they're less onerous for long periods.

I think it's a general limitation of the optical heart rate trackers that they aren't quite "24/7". At least on all the Android Wear devices that feature one, you have to ask it to take a reading, and it's pretty unreliable if you're moving. I didn't see it mentioned in the Apple coverage, but I assume it's probably similarly limited there?

My Basis watch takes readings regularly (not sure the interval once a minute, maybe) of my heart rate. Battery lasts about 3-4 days.

I would have bought one since that's exactly what I want but they're -still- not shipping outside the US. Think they may have missed their chance now...