I have been using the sport kit for a few months and I really like it. It is easy to use, uploading to the site is a breeze and it is making a difference in my workouts. I did have difficulty with callibration and I still think it is slightly off but it's not as bad as my pedometers and other tools I have used. I am rather suprised about the battery situation on the sensor and that i cannot recharge it. It appears that I have to buy a new sports kit shortly!