For instance, I rarely use the touchscreen on my Fitbit Versa because the shortcuts to my most-used smartwatch features are available via the three physical buttons on the watch. Gesture recognition is hit and miss on smartphone screens, nowhere near as responsive and accurate as on your smartphone screen, so bear that in mind too. Force Touch is a useful feature that has come to smartwatches, notably the Apple Watch. Just press down or tap the screen to activate different features.
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).
What’s on display?: Most smartwatches have full-colour displays, though the underlying technology will determine how good the screen looks. There has been a move towards AMOLED (active matrix organic light emitting diode) displays, as used in the Apple Watch which present a bright screen, crisp text and accurate colours. Fitness trackers tend to have lower-quality screens and may not present in full-colour, partly to save battery life.
When we compared the storage space of the Samsung Gear Sport with the other contenders, it didn’t have the most. With 4 GB — only a quarter of what you’ll get with the Apple Watch Series 3 GPS — you will have to manage your apps so you don’t run out of room. If you like to carry all of your music with you and you have an extensive library, you might run out of space with the Gear Sport.
For a device that gives you more of the functionality you enjoy with your smartphone, you’ll want to opt for a dedicated smartwatch. The leading players at the moment are the Apple Watch for iPhone users and the Samsung Gear S3 for those with Android phones. Apple Watch has its own operating system, Samsung employs its Tizen OS, and a host of other smartwatches use the Google Wear operating system.
Tizen is a Linux-based operating system for devices, including smartphones/tablets, in-vehicle infotainment (IVI) devices, smart TVs, laptops/desktops and other platforms. Tizen is a project within the Linux Foundation and is governed by a Technical Steering Group (TSG) composed of Samsung and Intel among others. Samsung released the Samsung Gear 2, Gear 2 Neo, Samsung Gear S, Samsung Gear S2 and Samsung Gear S3 running Tizen.
Dropping the phone: Some models of smartwatches in the Samsung and Apple line-ups feature a mobile network chip, allowing you to plug in a micro SIM card to make and receive calls, texts and emails and access the internet without being paired to your phone. It sounds great, but remember that the smartwatch has a very small battery, so relying on it for communications will drain the power quickly.
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.
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. 
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.