Other fitness monitors may soon eat the dust because none of them can measure willpower like the Armour39. It does so by measuring the effort you put into your workout, taking into account the activity duration, heart rate, intensity, type of workout, your gender, and weight. We love keeping track of our workouts because it turns the workout into a game and we think using the Armour39 will be one of the best ways to do this. For $150 you get a chest strap with a module that does all the measuring. You can sync the data through a mobile app or get the watch ($200) for an alternative display. The watch looks awesome by the way.