Millions of Americans rely on fitness trackers to keep them honest in their workouts. That’s why Consumer Reports has reviewed 17 top-selling models, testing their accuracy, ease of use, comfort, and feature sets. The fitness trackers we selected range from simple clip-on sensors to ambitious, wrist-bound plastic or rubber gadgets that add more sensors, more readouts, and a bigger price.

At the high end, we’ve found some great performers that combine accuracy and robust features. For instance, the watchlike Fitbit Surge ($250) packs GPS, smartphone notifications, and a heart rate monitor into a package that is very comfortable to wear. Among its competitors is the $200 Basis Peak, which won’t track your location but will monitor your heart rate, perspiration (another measure of exertion), and skin temperature. Unlike some other fitness trackers, both of these models have their own displays, so you can check your progress without reaching for your smartphone.

Among the lower-priced simpler fitness trackers we tested are several that deliver the most critical fitness data and offer other useful features. For instance, the Microsoft Band ($150) not only tracks your steps and heart rate but also lets you get email and text notifications right from your wrist. The stylish Withings Activité Pop ($150) looks like a regular watch but has a small dial that also shows you, on a scale of 1 to 100, your daily fitness progress. 

However, our tests also revealed some problems. Notably, some models, including the Jawbone UP3, experienced serious smartphone pairing and syncing problems.

If you’re in the market for your first fitness tracker—or just want to see if you need to bench the one you currently own—check our buying guide and Ratings.