For a little over a month, I've been getting off my subway one stop early and walking the rest of the way home. I've been playing soccer twice a week, and trying to drink eight glasses of water every day. I've been running more, eating better, but still not sleeping nearly enough.

I've been testing the Fitbit Flex, the first fitness wristband from the company that deserves a lot of credit for popularizing wearable fitness devices in the first place. From its namesake Fitbit Tracker to the newer One and Ultra, the California-based company has typically been known for devices that clip to your shirt or your pants and track your every movement. But every Fitbit user seems to have a tale of a lost or accidentally machine-washed tracker, so the company came out with the Flex. It's a $99 bracelet that purports to help you be more active, eat better, sleep better, and become far more attractive to the opposite sex. (One of those isn't strictly true, but it kind of is.)

But you could fill both your arms with all the available gadgets that claim to do those things. From Jawbone to Nike to Samsung to even a slew of apps for your phone, there are a million and counting ways to track your activity. So what does Fitbit offer that makes it special? Why should you spend $99 on the Flex over an Up or a FuelBand, or a free iPhone app? After lots of exertion in the name of journalism, I think I have an answer.