[zapt02]

Google Fit would probably be the smartest choice, because it has support for different hardware vendors. For example, Withings has Google Fit integration so you'd get their range for free.

[this-dang-guy]

Ups for google fit. I can tie my Pebble into that (at the moment), so it'd give me a leg up.

So to speak.

[fiftyacorn]

I didnt like the API compared to other vendors. It was quite basic and a much lower level. The plus side is vendor support