There are Pros and Cons for every gadgets.In this case too the same applies.If you just need the pros ,look the below listing..thank you ..
-Affordable piece of wearable
-Long battery life (up to 30 days as advertised)
-Water Resistant (you can wear it as you shower)
-Decent distance/step counter for sports junkies or those into health/fitness tracking when doing exercise/workouts.
-Sleep tracking feature is accurate and interesting.
-Able to switch band colours (blue, green, pink, blue, yellow), band comes in default black however. There seems to also be plans for a necklace accessory in the future.
-Able to alert users to phone calls and other notifications (very useful if you are prone to missing calls, but the phone has to be within the Bluetooth detection range).
-Able to unlock phone without the need to go through security/password screen when in proximity to the phone. (However, smart unlock feature is only supported on miui rom and android lollipop - thanks to -sLay- of MIUI forum for highlighting this point)
-Can operate on its own without the need to be close by to the phone (even when the phone is switched off).