Took my new AW S2 on a 35 mile trip up Whitetop mountain in SW Va this morning and also snapped on my HR chest strap and my Garmin bike computer to really test out and compair the AW and my Garmin which I know is accurate. To my amazement the Watch was almost dead on with my chest strap HR the entire 4.5 hour ride. The distance and speed was exact also. I couldn't be happier with the Watch, I don't feel the need to take the Garmin and chest strap biking with me anymore. This afternoon we used it on a 3 mile walk using the Watch outdoor walk exercise app and my battery is still at 55% with all this use, very happy on that part also. After all that exercise in one day I do think it's bed time lol.