The Asus ZenWatch is one of the most affordable high-end smartwatches on the market. (David Becker / Getty Images)
The Samsung Gear S smartwatch is distinctive not only for the curved screen but also for having embedded Wi-Fi and 3G cellular connection capabilities. (John Locher / AP)
The Sony Smartwatch 3 is one of only a couple of smartwatches that have built-in GPS. But some users have found the tracking -- and other features -- unreliable. (Sony Mobile / AP)