Most fitness trackers are glorified pedometers. The same pedometer technology we have been using for 30 years with some extra software to make it look more modern. To really track your workouts and help you improve, you need a much deeper level of information collection and a more mature set of data analytics tools.
Over a year ago, I loved the idea of a fitness tracker called Amiigo (link).
Unfortunately the Amiigo is more than a year late to deliver their product and updates aren't very comforting. What I liked about the Amiigo was that was supposed to measure pulse & skin temperature in addition to the standard array of sensors so it could determine what exercise you are performing and how hard you are really working out.
Now a new entrant to the game called Atlas (link) is making some interesting promises. Like the Amiigo, it is able to identify exercises (differentiating between similar movements like jumping rope and jumping jacks). It doesn't have all of the sensors that the Amiigo has but it seems much more capable than other quantifiable self devices (Shine, Nike Fuelband, Fitbit, etc).
They intend to make the app both IOS and Android compatible.
It's important to remind you that this is still being developed by a small smart up and is dependant on funding from IndieGogo (link). Keep in mind that many of these great ideas never materialize or come to market months to years late.
I think this is a great little device and it would be fantastic if they can get it to market. We'll just have to wait and see.