I have a fitbit zip, which I love. It does the best job of tracking my steps. My SPAT did a much more accurate job of tracking my mileage, even though my stride was set the same in both. I always wore both of them. After I installed my SPAT, it tended to override the Zip on SP. Now it says I have 0 exercise minutes almost every day, and I'm trying to figure out how to get that fixed. Annoying.