Which fitness bands are worth buying?

We spend a lot of time in front of our computers, which could be why we're so keen to track all the times we actually step away from our screens and get a little walking or running done. To that end, every manufacturer seems to be coming out with a fitness band to brandish on your wrist. But when one wearable looks like the others, and they each operate in different ecosystems, it's hard to know which will best suit your needs. We've taken a look at a few recent releases and their reviews, narrowing the field to seven of the better models out there -- plus one you should avoid.