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.
Basically, smartwatches are wearable-technology devices that maintain a relatively persistent wireless connection to your mobile device—usually a smart phone—and can receive notifications of incoming calls, texts, instant messages, social-network updates, and more, from that device. Some can also let you accept and conduct phone calls right on the watch. And even newer models (the Samsung Gear S, for one) can act as smart phones all on their own, without needing a paired phone nearby.
Battery life and charging options: Charging your smartwatch is a hassle and the biggest downside to trading in your manually-wound or button battery-powered watch. A Fitbit Versa might last 3 - 4 days between charges, but a smartwatch like the Samsung Gear Sport or Apple Watch will need recharging every couple of days and sometimes every night if you are tapping on the screen regularly and using its apps.
My personal favorite watch for Android on the market today actually isn’t an Android Wear device, rather coming from Samsung and running atop Tizen. The Samsung Gear S3 Frontier is all the smartwatch you’ll ever need, with a sporty, circular gray design with a 1.3-inch Super AMOLED display that is the best I’ve personally ever used and is protected by Corning Gorilla Glass SR+.
It has all the sensors you might want if you’re an avid runner, but it goes so much further. If you’re a hiker, you’ll love the altimeter, air pressure read-outs, the clock showing the sunrise and sunset times, compass and the indicator of the day’s tide levels. You can also download map data for use offline, meaning if you’re the Bear Grylls type then you’ll be well prepared.
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).
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. 
All but the Martian Notifier claim some degree of water resistance: the LG, Samsung, and Motorola models can survive underwater up to 1 meter for 30 minutes, the Cookoo2 up to 100 meters, and the MetaWatch up to 3ATM, which is equivalent to 30 meters. Only the Martian and Motorola models claim to have scratch-resistant screens (the Martian has an anti-scratch acrylic crystal and the Moto 3 uses Gorilla Glass 3).
Smart watches are here to change the way you live. Now you can power through your workouts while the latest technology keeps track of your every move, check your calendar and keep an eye on the weather forecast wherever you are. You can also sync your smartphone with your watch, so you can check your texts, see who’s calling and receive notifications while keeping your iPhone 6 Plus safely tucked away.