I bought the fitbit flex fitness band as a gift to my mom and I am not impressed with the performance. Its lacks too much of time.
There not accuracy with which the bank tracks her fitness activity and sleep. Its privide wrong information.
The band tracks number of steps taken, calories burnt, distance travel, active time but its always lack in between tasks this stopped working. it dont told you about sleep pattern like hours slept, deep sleep, almost awake sleep time. This task is a necessory part of any fitness band. There is an app which complements the band really well.
But when the band dont work properly then what you do with app. both are connected via Bluetooth. The draw back I can really think of is the touch sensitivity. Its not responsive. some time the band needs a hard press where as a soft touch is sufficient in other times. So this need improvement. The price we pay its an absolute not a value for money.battery back up is also not that great. I DONT reccomended any one.