Apple Watch (1st generation and Series 1) Apple watchOS No 8.2+ (1st generation) 10.0+ (Series 1) Apple S1 (1st generation) Apple S1P 4.0 LE ] From paired iPhone No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes IPX7 Digital 1.7 / 1.5 319x390 / 272x340 AMOLED 1.5 250 / 205 Lithium-ion 42 mm / 38 mm 12.46 / 12.3 36.2 / 32.9 Varies Yes Yes No
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. 
If you’re into premium smartwatches, the Montblanc Summit is the latest option hitting watch shops around the world. Out of the box, it runs atop Android Wear 2.0 with the standard specifications — Snapdragon Wear 2100, 512mb of RAM, and 4GB of storage. There’s no NFC or LTE on board, but the watch does feature a heart rate sensor and premium materials.
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.
First, there’s now an option of an LTE-capable model allowing for always-on connectivity. This is through the use of an eSIM inside and an antenna cleverly hidden behind the display. The great news is that your Apple Watch 3 will share the same phone number as your iPhone, whereas other LTE-capable smartwatches have required you to juggle two phone numbers. You’ll need to pay for an additional smartwatch plan for the functionality, however.
The new Diesel Full Guard 2.5 has a 47mmx56mm casing which is bigger than most Wear OS watches, and there’s a 1.39-inch display at the center of that. This new refresh of the watch also includes NFC for Google Pay support, a heart rate sensor, and built-in GPS. Diesel also says this watch will last two days on a charge from the 300mAh battery. The watch also has 3ATM water resistance.
Apple Watch is crisp, beautiful, high-resolution screen that’s smaller than an Oreo cookie. No surprise, Apple knows what they’re doing when they design a home product. Much like the other additions to the Apple suite, the Series 3 is sleek and stylish. Everything from the navigation to the screen layouts has been optimized to utilize the space given rather than be constricted by it.
The Misfit Vapor was originally launched with a proprietary operating system, but that was ditched for Android Wear 2.0. The Vapor has a 1.39-inch AMOLED display, Snapdragon Wear 2100 processor, 4GB of storage, 512mb of RAM, and a heart rate sensor. Those specs are fairly standard for Android Wear, but the Vapor also includes 5ATM water resistance which is a huge plus, and an assortment of software features added by Misfit.
Inside the Charge 3 are an accelerometer, gyroscope, optical heart rate monitor, and an SpO2 sensor for tracking blood oxygen levels. The Charge 3 is the third Fitbit device to include an SpO2 sensor, following in the footsteps of both the Fitbit Ionic and the Versa smartwatches. However, currently the SpO2 monitor lies dormant inside all of these devices as Fitbit hasn't made use of it yet.
For deeper integration with your Android phone, you can give Google's Wear OS platform a try with Fossil's $275 Q Control touchscreen smartwatch. It lacks GPS and support for NFC payments, which is why the Gear Sport is a better fitness-focused smartwatch for Android users, but Fossil's Google Assistant integration and stylish design make it a solid contender. However, smartwatches with Qualcomm's new Snapdragon Wear 3100 processor start shipping in October, so you may want to hold off until we put them to the test.