Eddie Smith took the trouble to do something I've always wondered about. He compared iPhone and Fitbit step counts. Eddie tested the devices going up and going down, riding elevators, walking through nature, and even riding in a car. It's actually a really good read. To me, the most interesting datapoint was how close the devices were on step count over a 90 day period. I think that as motion tracking becomes standard issue on smart phones and smart watches, step counters are going to have to bring something to the table or they'll go the way GPS navigators and iPods..