I've had my vivofit for only a few days, but I noticed that when I take the dog for a brisk walk on my usual route, which I know is exactly two miles, the vivofit band measures it at 1.93, which is very close. If I wear the HRM, and then synch it when I return, the garmin connect creates an activity which says it is 1.3 miles, while the band measures the same 1.93.
I'm not going to get into the calories, because that is hilariously not close to being correct.
I am amazed at for a product with so much potential, it has been so poorly executed. I am already very much regretting my purchase of this weak product.