I started using Google Fit on my phone last week.
Google fit is yet another app for recording exercise activity, but it’s a bit different from others in that it’s very passive. It runs all the time and tries to tell you how long you spent walking/running, how far, and how many steps.
It seems to do this without GPS (because it would kill your battery), so it’s not very precise, but it’s also not completely imprecise and I’m a bit mystified how it works out where you are (maybe signal? Or has Google mapped wifi networks and router mac addresses?!). That means that it doesn’t map your route, just your rough location.
It’s pretty smart – it knows when you’re walking, it knows when you’re running, and it also seems to know that you’re sat on a train rather than running really fast.
So… summary: it seems to get walking distance reasonably accurate. I have only run once with it so far but it was missing a kilometre (6 in reality vs 4.8). I don’t know about the step counter; it guessed my run had me doing 145 steps per minute which seems a bit low really…
It’s probably more interesting to see overall trends rather than absolute data.
Battery life is definitely reduced, but I don’t think it’s by enough that I’ll have to charge it more frequently than I do already (I hate batteries).
The privacy implications are of course absolutely horrifying, but that’s smartphones for you.