The Fitbit calories burned accounts for burned calories during sleep & also calories burned just to function every organ in body as a result you get a much better or accurate breakdown of calorie count out, Apple Watch doesn't do this am I wrong?
Fitbit is much more accurate in calorie in calories out I have given up on the health program on Apple Watch because it isn't accurate for my workouts, you are already behind about 450 calories when you wake up every morning
Apple Watch, watchOS 2.1, Accuracy on calories counted
