I got my watch over the weekend and finally got around to a run day and wanted to compare how accurate the apple watch is to my trusty Nike watch. I've been using my nike watch since 2012 for logging runs and it has never failed me. I trust the Nike watch to be 98% accurate with tracking. As you can see from the images below the Nike watch is considerably off compared to the Nike especially the run from 6/2. I ran with the watch and phone both days to get as accurate a reading as possible. So don't count on using your watch to keep great tracking of your outdoor fitness activities.