Its only drawback is its use of Samsung’s own Tizen OS. Tizen is a custom OS that’s based on Linux. On paper it’s pretty good, letting you pair the Gear S2 with any Android smartphone, not just Samsung Galaxy phones. But it’s nowhere near as developed as Wear OS, which itself isn’t perfect. There aren’t nearly as many apps available as the Wear OS app store, but the core functionality is at least present from what is available.
If you don’t need your smartwatch to look business-casual, you want more fitness and exercise features than our top pick, or you’re a Samsung loyalist, the Samsung Gear Sport is a better pick for you. (You can use the Gear Sport with non-Samsung phones, but doing so requires that you install at least four apps.) The Gear Sport handles all the casual notification and message-triage functions of a smartwatch about as well as our top pick—with the exception of voice transcription—but it adds heart-rate monitoring, GPS tracking, swim tracking, and built-in reminders to move throughout the day. It doesn’t do all of these things perfectly, but it does just enough to make for a generally useful smartwatch, with great battery life and a clever interface.
On-Screen Workouts/ Connected GPS/ Bluetooth/ Smartphone Notifications/ 4 Day Battery Life/ Heart Rate Tracking/ 15 Exercise Modes/ SmartTrack/ All-Day Activity/ Female Health/ Sleep Tracking And Stages/ Cardio Fitness Level/ 3-Axis Accelerometer And Gyroscope/ Optical Heart Rate Monitor/ Color LCD Touchscreen Display/ Water Resistant To 50 Meters/ Charcoal Woven Strap & Graphite Aluminum Finish
The Apple Watch boasts cutting-edge smartwatch tech including mobile payments with Apple Pay, stand-alone GPS, full waterproofing up to 50 meters, and thousands of apps. The user interface is very simple and attractive. It's easy to use and it has advanced, easy-to-use fitness tracking features, thanks to a plethora of sensors and an excellent heart rate monitor.
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. 
Smart watch Company OS Android version iOS version CPU Type Bluetooth NFC Developer Options GPS Notify Link Loss Alert Notify Missed Call Notify Timer Notify View Content Call Conversation Find My Phone Voice Control Respond to Notifications Notify Sound Notify Backlit Screen Notify Vibration Ambient Light Sensor Gyroscope Magnetometer Multi-touch Accelerometer Dust and Water Resistance Clock Display Type Screen Size, Inches Screen Resolution, pixels Pixel density, ppi Display Technology Average Battery Life, days Battery Capacity, mAh Battery Technology Case Diameter, mm Case Thickness, mm Wrist Band Width, mm Weight (main unit+watchband), g Wristband Options Replaceable Wristbands LED Flashlight
Being able to customize the watch faces and layouts, made the Series 3 a shoo-in for our list of best smart watches. Much like you can customize the homescreen on your iPhone, you can change the layout of apps and even display the weather. While you can’t opt for third-party designs, you do have 12 different watch faces to play with. Tinker with color schemes, add or remove widgets (called “complications” on the app), and decide whether you want to have all twelve faces available on your watch (we always like having options), or cut back.
In 1998, Steve Mann invented, designed, and built the world's first Linux wristwatch, which he presented at IEEE ISSCC2000 on 7 February 2000, where he was named "the father of wearable computing". See also Linux Journal, where Mann's Linux wristwatch appeared on the cover and was the feature article of LJ Issue 75. Seiko launched the Ruputer in Japan - a wristwatch computer with a 3.6 MHz processor. It was not very successful, since instead of a touchscreen it used a joystick-like device to input characters (much like high scores in arcade games), and the small screen with a resolution at 102x64 in 4 greyscales made it hard to read large amounts of text. Outside of Japan, this watch was distributed as the Matsucom onHand PC. Despite the rather low demand, the Matsucom onHand PC was distributed until 2006, making it a smartwatch with a rather long life cycle. Ruputer and onHand PC applications are 100% compatible. This watch is sometimes considered the first smartwatch since it was the first watch to offer graphics display (albeit monochrome) and many 3rd party applications (mostly homebrew).
348 x 250 Resolution Touchscreen Display/ Color LCD/ Dynamic Personal Coaching/ PurePulse Heart Rate/ Popular Apps/ SmartTrack/ Sleep Stages And Insights/ Store And Play Music/ Water Resistant Up To 50M And Tracks Swims/ Built-In NFC Chip/ All-Day Activity/ Built-In GPS/ Multi-Day Battery/ Multi-Sport Modes/ Smartphone Notifications/ Charcoal And Smoke Gray Finish
The first digital watch, which debuted in 1972, was the Pulsar manufactured by Hamilton Watch Company. "Pulsar" became a brand name which would later be acquired by Seiko in 1978. In 1982, a Pulsar watch (NL C01) was released which could store 24 digits, making it most likely the first watch with user-programmable memory, or "memorybank" watch. With the introduction of personal computers in the 1980s, Seiko began to develop computers in the form of watches. The Data 2000 watch (1983) came with an external keyboard for data-entry. Data was synced from the keyboard to the watch via electro-magnetic coupling (wireless docking). The name comes from its ability to store 2000 characters. The D409 was the first Seiko model with on-board data entry (via a miniature keyboard) and featured a dot matrix display. Its memory was tiny, at only 112 digits. It was released in 1984, in gold, silver and black. These models were followed by many others by Seiko during the 1980s, most notably the "RC Series": During the 1980s, Casio began to market a successful line of "computer watches", in addition to its calculator watches. Most notable was the Casio data bank series. Novelty "game watches", such as the Nelsonic game watches, were also produced by Casio and other companies.
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.
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.