Bests & Worsts Reviews from Amazon

I really want to like this bc the app is great, the steps are very accurate, the sleep monitoring is cool but the main goal of these fitness trackers is to encourage more fitness...which it has. However, every time I start to break a sweat on the treadmill my heart rate monitor reading disappears and I get the "--" on display(see pic). This is so frustrating bc this is when I need it most. I have tried different positioning of the Fitbit to no avail. I'm surprised by all the very positive reviews here...maybe most users are just casual users who use for steps. There seems to be tons of similar complaints on forums. I can live with hr being slightly delayed or a few bpm off but I can't have the hr turn off completely every time I break a sweat. Looks like a return is in near future. Edit: So I have found a semi workable solution to the sweating problem which causes HR to turn off. I have been wearing the fitbit about 2 fingers above wrist bone with a tighter fit(as directed). then below on my wrist I wear a sweatband. This seems to greatly diminish the HR from malfunctioning. Edit2: I have had this about 3 months now and ever since i have gone to the approach above to fix the heart rate I have had zero issues and it has performed very well. upgrading my rating. Edit 3: after about 8 months the original band broke from normal use. Fitbit customer service replaced it for free. Thanks.