I have the Charge 4 and am very disappointed. Several of the features are not working properly. The sleep feature can't properly reflect the full night because I have to get up 5-6 times to go to the bathroom. It only reflects a small portion of the night. I've contacted customer support and tried their suggestions without any success. The number of stairs climbed during the day is very inflated. Some days the watch says I have climbed 10-12 stairs when I first got up in the morning.