I have the Fitbit One because I don't like wearing anything on my wrist. I'm glad that I got this instead of waiting for the S Band. The free app will work on a number of phones, auto sync using Bluetooth and seems to have more options based on what I've read about the upcoming (maybe) S Band. The Fitbit stays charged for about a week. I've had it now for two weeks and I'm really pleased with it. I wasn't so sure when I purchased it but figured I could always return it if I was unhappy with it. Now, I have no intention of returning it and I'm even happier that I didn't wait around for Samsung to finally do something. The Fitbit is a great product and works really well.