To charge the watch, you have to clip on the charger and align it with contacts that you can't see when you're clipping. Why make it so complicated? There's no NFC for easy pairing, and you have to find the smartwatch app in the app market, download it, and install it on your mobile device. The Frame's display readability in bright sunlight was judged to be only good. It's relatively heavy, at 2.7 ounces (only the Toq is heavier).
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.
The Charge 3 works continuously throughout the day to track steps, distance, calories, floors climbed, and heart rate—the standard array of activity data. Fitbit has been tracking these metrics for so long, without making many significant updates as of late, that they are business as usual on the Charge 3. I appreciated that most of the watch faces available for the Charge 3 show your real-time heart rate, either in a corner or at the bottom of the rectangular display. I like being able to glance down and know my pulse.
Wirecutter writers have been researching, testing, and writing about smartwatches since early 2013, just after the first Pebble watches were shipped to Kickstarter backers. I’ve personally worn nearly every notable smartwatch since that first Pebble and have written about them for a number of publications, including IT World and Fast Company. I also have extensive experience with Android phones, having written the (since outdated) Complete Android Guide and numerous articles about Android. I also contribute to and help edit the Wirecutter guide to the best smartwatch for iPhones.
Smartwatches are relatively new gadgets, and their features are continuously improving. Each smartwatch needs to synch to your smartphone to get enhanced features. Once linked, depending on the model of smartwatch, you can forward emails, text messages, GPS directions and more to your wrist. Some smartwatches even have built-in microphones and speakers, allowing you to make phone calls. Calls are routed through your smartphone, just like when using a Bluetooth Headset. The Samsung watch—dubbed the Galaxy Gear—also has an integrated camera, so you can snap spontaneous photos without ever picking up your smartphone. Of course, ever smartwatch also functions as a traditional digital watch when not linked to a smart device. As the technology matures, expect to see more advanced features and perhaps even complete phone functionality built in.
"Sport watch" functionality often includes activity tracker features (also known as "fitness tracker") as seen in GPS watches made for training, diving, and outdoor sports. Functions may include training programs (such as intervals), lap times, speed display, GPS tracking unit, Route tracking, dive computer, heart rate monitor compatibility, Cadence sensor compatibility, and compatibility with sport transitions (as in triathlons). Other watches can cooperate with an app in a smartphone to carry out their functions. They are paired usually by Bluetooth with a smartphone. Some of these only work with a phone that runs the same mobile operating system; others use a unique watch OS, or otherwise are able to work with most smartphones. Paired, the watch may function as a remote to the phone. This allows the watch to display data such as calls, SMS messages, emails, calendar invites, and any data that may be made available by relevant phone apps. Some fitness tracker watches give users reports on the number of kilometers they walked, hours they slept, and so on.
The top smartwatches that debuted at the 2017 Consumer Electronics Show included the Casio WSD-F20, Misfit Wearables Vapor and the Garmin Fenix 5 series. Apple released on September 22, 2017 their Apple Watch Series 3 model which offers built in LTE cellular connectivity allowing phone calls, messaging and data without relying on a nearby smartphone connection. 
For all of you outdoorsmen, Casio returned to IFA this year with its latest Pro Trek watch. The Casio WSD-F30 takes the same great features of previous generations and slaps them inside of a slightly slimmer body. The 60.5mm × 53.8mm × 14.9mm body is still pretty huge, but it’s considerably smaller than what came before it and still maintains 5ATM water resistance, MIL-STD-810, and even low-temperature resistance.
No other smartwatch offers this much variety and customization, especially when it comes to female-friendly options. The Apple Watch is the only smartwatch I've ever worn regularly each day for months on end. I've reviewed dozens of WearOS watches, and although many of them are nice looking as well, they're not as fully featured or easy to use as the Apple Watch.
The Apple Watch Series 4 is now on sale, and it's the best smartwatch you can buy right now. The redesigned device, which starts at $399 for the GPS model and $499 for the cellular version, is the best smartwatch you can buy. It has a larger display and slightly bigger case size while retaining the same rounded square design the watch is known for. Even more importantly, Apple received FDA clearance for a new electrocardiogram feature that can take a 30-second EKG and diagnose atrial fibrillation.