I'm using it for 1+ month and I really love this band. The sleep mode is very accurate and the steps are almost the same with those from S Health application on my Note 3. I love that the band use micro usb for charging.
Great battery life, it last 6 days on my case.
The great part of this band, is the notification system with the vibration, because when I drive I can't hear the phone, because the music is too loud :)
The things I don't like: the vibration after the update is too strong, the alarm still vibrate even if I put the band on day mode, which means I'm awake and no need an alarm. I'm still waiting for the car and bicycle options, which right now are only available for Xperia phones.