The Samsung Gear S3 was our prior pick for Samsung phone owners because of its smooth dial rotation and interface. But it was notably large, with a 46 mm face, and the Frontier model was half an inch thick, notably bulky even for a smartwatch. The Gear Sport, our runner-up pick, is less bulky, less expensive, less overtly masculine-styled, and provides most of the same features, minus the LTE option.
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 screen is great, and the pre-installed watch faces make it stand out from rivals. Android Wear feels very samey across all devices, but it's a well developed OS. It's reasonably intuitive and simple, but there's a little too much swiping and tapping on the small screen. It also works across both Android and iOS, although iPhone functionality is limited (no apps etc.)
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.