There is another "me too" entry into the wearable fitness tracker market nearly every day as this market is HOT. I did a comprehensive review of wearable fitness trackers but lets cut to the chase, the best of the best.
If you are overweight with poor health and all you need is a device to count your steps and help motivate you to walk a certain number of steps in a day then any of these wearables will do the job just fine - pick the one you think looks best … or install an app on your smartphone that will count steps. On the other hand, if you are interested in a performance tool, my highest recommendation goes to the Polar loop because you can turn it into a serious performance monitor by adding the optional Polar H7 heart rate monitor. Of all the wearables - FitBit, FuelBand, JawBone, Misfit Shine, Sony Core, Nabu Smartband, BodyMedia, etc the Polar Loop is the only one that allows you to upgrade it with a bluetooth chest strap heart rate monitor.
If you consider yourself an athlete and have a smartphone then consider investing in a real performance monitoring tool. The cheapest way to do this is to add bluetooth Polar H7 heart rate monitor to your smartphone, they only cost about $60. Then get a Wahoo blue SC sensor for your bike if you are a cyclist and a polar stride foodpod for your shoe if you are a runner. With $200 worth of sensors you can get a high powered, accurate, GPS tracking, fitness performance measuring device.
OK, I know I said Top 3 and I have not listed three yet. The last two will make you scream "no fair" because they are not sexy or cool looking like the new crop of bracelets but they are serious performance monitoring tools instead of mere step counters. These two devices have been around for years and they work well and the companies have good track records of quality products:
Both these devices have GPS and footpods for impeccable accuracy in determining speed and distance as well as optional heart monitors (must have) for optimizing performance.