There have been numerous reviews I've come across from various tech sites and most come off with a negative view on the Band. But in most of those reviews, the writers stated incorrect and completely misleading information. Also, it seems a lot of the time the reviewers do not have long-term experience in fitness wearables.
I've used a fitness wearable for over several years. I've used Polars, Garmins, Fitbits, and Mios. I've used optical H/R and chest straps. I've had the Band since release day and I love it. I can admit the fitness data from the device produces different value then from other brands, however if you understand and set a base-line it has all one would need to figure out fitness goals. I love the integration and notifications with my 830 also.