Buy this!!! It is so accurate and VERY helpful in tracking your daily activity. In comparison to the FitBit, it works the same, if not better--and it is only a FRACTION of the price! I only paid about $35 for mine in-store, whereas a Fitbit is about $100. The benefit to using Avia is that you can see how many steps you've taken and approx. how many calories you've burned as you're going about your day. You don't necessarily need to use the app to mark your activity, but it certainly helps and that is free.
I love this :)