[roxtar]

Look pretty slick. It's interesting that it's marketed as a fitness device but is actually a smart watch. I own a Garmin Forerunner 305 which can last 6-8 hours of active use. I know that the recent Garmin devices last close to a day. The Microsoft Band doesn't tell us how well it does on battery with the GPS -- without the GPS it claims 48 hours.

[pedalpete]

If you're using gps to track running and such, you aren't running 24 hours a day, so you can save battery by turning it on and off. I think that's a great feature. But it would have been nice to say 'GPS' time, like phones describe 'talk-time'.

[jackalope]

There are times I wish I could leave GPS tracking on all the time, with a simple way to add markers either now or later, and with the ability to share the data with any app I want. There are times I just want to hop on my bike and ride without doing some dance with a finicky GPS app that I have to remember to stop at the end (and hope it doesn't crash during my ride).

[eli]

For what it's worth, any Android phone with Google Now already can track you (albeit without super high resolution) 24/7. It's actually kind of cool; it looks at where you are and how fast you're going to infer walking vs biking vs driving.

[roxtar]

>If you're using gps to track running and such, you aren't running 24 hours a day

I run and cycle. I and many people I know do cycle ~ 12 hours in a day, while training. Right now the choice among road bikers I know, is the Garmin 810 which lasts that long with continuous use.