I realize it's an older topic but I would like to add something.
A month ago I bought the Garmin vivosmart and I'm loving it.
It doubles as a watch, has an OLED touch screen and everything in your NC can be displayed/read on the vivosmart. Love that feature but it might not be yours if you receive a lot of notifications.
I use it instead of my alarm clock too, vibrations wake me up.
The band is not as wide as the one from the vivofit, it's water proof and can be connected to a ANT+ heart rate monitor.
Light weight and comfy to wear.
The app is OK, could be better but does all I want it to do.
I owned the Polar Loop (besides registering way to many steps) it had problems with the Bluetooth connection so syncing was a pain.
Glad, as I could return it as DOA and choose the Garmin Vivosmart instead.