The Jawbone UP is an enticing device, most of its reviewers begin. Then the bad news hits. The wristband device for measuring your every move is prone to simply freezing up, and it's negating the otherwise desirable functions of a device that was supposed to be a hit.

"A Potentially Wonderful Thing That You Should Not Buy," Gizmodo warns. And its iPhone app is crashy too, says Fast Company. The Detroit Free Press sees the detour into fitness monitoring as a mere "blip" for a firm that will go back to successfully making Bluetooth headsets and speakers.

What's the deal?

There's much to commend about the device and the concept, reviewers say, especially a rubberized bracelet that can be easily worn at all times, using an internal sensor to measure steps, monitor sleep patterns and otherwise harvest data to be plugged into the iPhone. But the failure rate of those bracelets is dooming the reviews, and possibly the sales for a product whose fans included Mark Zuckerberg and Ashton Kutcher, and who had lined up $120 million in venture capital. Gizmodo's Mat Honan, for instance, took the gadget off his holiday gift list.

Here's his coup de grace, a sign that the company has a problem it really must fix, if they want to sell this thing:

As you'll see all over the Jawbone forums, and as was my experience, these bracelets have an unacceptably high failure rate. And according to people posting there, even some of the replacement bands are failing.

The bottom line is that Jawbone is knowingly selling defective products. As much as I want to love this product, because when it worked it was amazing, instead I'm going to give a strong recommendation against buying this for now.