To calculate the overall star rating and percentage breakdown by star, we do not use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
Pros: Small and light. Able to tell me a lot of information. GPS works fine, maybe need some time (~ 1 minute) to detect location. Very impress with the body battery data. Cons: battery seems to drain fast. Have to charge about every 4 days.