The Fitbit Ionic works fine as a Fitbit tracker, but despite being more expensive than our picks or the Apple Watch Series 1, it lacks many smartwatch functions you’d hope to have. It passes notifications from your phone to the watch, but you can only respond to some of them (with only five quick reply lines); and dismissing them (either one by one or as a group) involves annoyingly hard presses and long scrolls. Syncing music files and offline Pandora playlists requires you to use a desktop app, which is laborious. Two Wirecutter writers who tested the Ionic also had trouble setting it up to work with their Android phones (a 2015 Moto X Pure and a 2016 Samsung Galaxy S7) and had to perform significant troubleshooting to get their data to sync. The Ionic’s battery life, even while using GPS for outdoor exercise tracking, is its most impressive feature, lasting at least five days in one test and nearly seven days in another. The Ionic is most useful to Fitbit enthusiasts who want to track outdoor exercise without bringing a phone; it’s not a good option if you’re looking to deal with incoming information.
The SmartWatch 2 is a streamlined version of Sony's first smartwatch (which went on sale in 2013) with a number of new features. The SmartWatch 2 has a thin bezel; it's almost all screen, which gives it a modern, sleek look. You choose from one of two strap designs, black plastic or black stainless steel, or you can swap those out for a leather strap in one of seven colors ($20 each). We tested the model with the plastic strap, which is light and flexible and can fit close to your wrist.
Garmin has been putting out go-to smartwatches for sports lovers for a while now. Running, cycling, swimming, golf - Garmin has had us well and truly covered. Despite the Forerunner name, the 645 Music is more in the mould of the Vivoactive 3 Music. It's got a similar look and also brings the music this time. This helps make the Garmin more of a smartwatch rival to the Apple Watch, Samsung Gear or Fitbit Ionic than before.

Our top pick for most people is the Apple Watch Series 4 with GPS (starting at $399), which has a huge display, ultra-fast processor, Raise to Speak Siri, fall detection and a built-in electrical heart rate sensor for taking on-the-go electrocardiograms. It also runs watchOS 5, which makes the watch even more useful with automatic workout-tracking, offline podcast playback and a Walkie-Talkie voice chat feature. 
×