The best device for you will depend on your current fitness levels and needs. Most devices measure footsteps, distance travelled and calories burned. Although some smartphones already do that, many stand-alone devices also monitor your sleep patterns. Some even notify you about messages and calls on your wrist.
Consider this as you shop:
— What do you need a fitness tracker for?
If you're currently inactive, you might want a simple device that sets goals such as 10,000 steps per day. However, devices that only do this will probably end up in a drawer after a few months. Either you've become active and don't need the reminders, or you've gotten annoyed by the pestering.
Think beyond that initial step and look for something that offers more details on your activities. Perhaps that's a heart-rate monitor to gauge the intensity of your workouts. Withings' Pulse O2 ($120) also measures blood-oxygen levels, which the company says could be useful if you're training at high altitudes.
A device that offers message notifications might be overkill. You're better off with something that's great at a few things rather than mediocre at several things. If you need notifications, get a separate smartwatch. Plus, many fitness trackers are meant to be worn around the clock, and those that offer extensive notifications tend to be bigger because they need bigger displays.
— How much work do you want to do?
By this, I don't mean how much workout. Rather, are you looking for something that's completely automated? With the Fitbit Charge ($130) and the Basis Peak ($200), just wear it on your wrist. It automatically figures out when you're moving or when you're asleep. Many others still require you to manually switch to night mode at bedtime. Meanwhile, several devices are smart enough to tell when you're walking, running or biking.
That said, you might get more out of a device that's not automated. Too often, my runs get split up into multiple sessions just because I stopped at an intersection or water fountain. With Samsung's Gear Fit ($150) and Adidas' Fit Smart ($199), you have to manually start the logging. That keeps you in control, but it's also more work on your part.
— You are what you eat.
A few devices have companion apps that also monitor how much you eat. With Fitbit's app, for instance, you enter your meals (or scan a barcode if you're using an iPhone). It tells you whether you can eat more or need to exercise more to meet any weight-loss goals. Keeping track of my meals is too much work for me, but those serious about weight loss will appreciate the feature.
— Notable features.
It's annoying if your device runs out of battery in the middle of a workout. If the workout doesn't appear on your app, it's as though you never burned those calories. The battery in Jawbone's Up Move ($50) lasts several months, compared with the few days or few weeks that other devices offer.
While most devices let you sync data to a companion app, the Runtastic Orbit ($120) works in reverse as well. You can get more accurate distance readings on Runtastic's app because the phone has GPS. If you have the app running, data on pace and distance will display on the Orbit on your wrist.
— The elusive GPS.
A major shortcoming with most of these devices is their inaccuracy. I've found distance estimates based on footsteps tend to give me too much credit.
Some of these devices offer calibration, but a better approach is to get a device that tracks distance based on GPS. The Microsoft Band ($200) and the Fitbit Surge ($250) do have GPS, but they are currently in limited release. Sony's SmartWatch 3 also has GPS, but it's more smartwatch than fitness band. There will likely be additional devices with GPS unveiled at the International CES gadget show next month.
If accuracy is important — and it is for me — I suggest waiting. Many people, though, will be fine with the estimates provided by the slew of fitness devices already out.