You can also use devices that support the Google Wear operating system in conjunction with an iPhone as well as a Samsung Gear device that runs Samsung’s own Tizen operating system. But Google Wear and Tizen devices are designed to pair with smartphones using the Android OS, so you won’t get full functionality when pairing with an iPhone. For instance, some Android smartwatches carry Samsung’s smartwatch line-up and naturally enough, work best with Samsung smartphones, but are still compatible with Android-powered Huawei or Nokia phones.
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 Moto 360 was the first round smartwatch we got our hands (or wrists) on, and the design was a standout, for us. It looks like a traditional watch and fits more comfortably than rectangular smartwatches, but still packs the full functionality of an advanced smartwatch. Like the LG G Watch and Samsung Gear Live, it runs the Android Wear OS, allowing voice commands and pushing relevant information to the wearer.
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).
Fossil’s Q Explorist and its smaller-wrist counterpart the Q Venture are well-made, responsive, fashionable Wear OS smartwatches that offer a lot of color and band options, making them the best option around. They ably run Wear OS (more on the pros and cons of Wear OS itself in a bit) and convey your phone’s notifications to your wrist. Their buttons engage with clean clicks, the Explorist’s center crown moves through lists and notifications much more effectively than swiping, and both screens are responsive and clear.
To round off the Gear Sport’s positives, it has very solid battery life (almost never less than 50 percent of the battery remaining after a full day), it can play offline Spotify playlists (even for free accounts), and if you have a Samsung phone, it integrates easily with most of the apps you have installed there. The Gear Sport is easier to set up with a non-Samsung Android phone than previous versions of the Gear watch, too. It still requires the installation of at least four apps and some regular updating, but it’s not the hour-long trial-and-error of other Gear watches we’ve tested, working reliably in our testing.
If you’d prefer your smartwatch looked more like a piece of jewelry than a small computer on your wrist, you’ll like Skagen’s Falster range. The straps of these slimline watches come in a few different leather or stainless steel options but coupled with the included minimalist watch face designs, they all look sleek and stylish in a way few other smartwatches manage.
Using your voice with the Google Assistant function built into the Q watches (and every modern Wear OS watch) is generally okay, though only roughly 80 percent reliable. The combination of a microphone on the side of your watch, a Bluetooth connection to your phone when you’re away from Wi-Fi, your phone’s cellular Web connection, and the imperfect acknowledgement of human speech by Google Assistant do not make for anything near a 100 percent success rate. When it works, Google Assistant makes you feel connected and advanced; when it fails, you can be seen as a person who asks their wrist about the capital of Malaysia. This is more a reflection of the state of connectivity and digital assistants than of the Q watches themselves—or any Wear OS watch, for that matter—although in our experience Wear OS watches fail on voice queries more often than Siri on the Apple Watch. That said, voice dictation on the Q watches is far more reliable, at least when it comes to recognizing words and phrases, than Google Assistant. If transcription fails, it’s more likely to be because of the watch/phone connection than the watch mishearing your words.
The Series 4 now has several new health-focused features, which are very intriguing, including the ability to detect when you fall and even alert emergency contacts if need be, as well as an electrical heart rate sensor that works with an app to alert you to heart health issues. The electrocardiogram (ECG) app has been certified by the Food & Drug Administration, but it's not out yet.
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+.
As for the tech inside, the Q Venture won't let you down. It runs WearOS (previously known as Android Wear) and works with thousands of apps on the Google Play Store. You can answer texts, interact with notifications, and choose your own watch face — just like you would on any other smartwatch. Fossil has lots of nice watch faces in feminine colors, too.
For most people, the most useful thing a smartwatch can do is relay phone notifications to your wrist so you can check them without having to pull out and wake up your handset. You can still be distracted by whatever is buzzing you, but it’s easier to quickly see whether something is important or not. Often you can interact with that notification—by acknowledging it, dismissing it, or replying to a message with voice dictation, a pre-written response, or (awkward) finger typing or swiping—right on the watch.
A smartwatch is a wearable computer in the form of a wristwatch; modern smartwatches provide a local touchscreen interface for daily use, while an associated smartphone app provides for management and telemetry (such as long-term biomonitoring). While early models could perform basic tasks, such as calculations, digital time telling, translations, and game-playing, 2010s smartwatches have more general functionality closer to smartphones, including mobile apps, a mobile operating system and Bluetooth connectivity. Some smartwatches function as portable media players, with FM radio and playback of digital audio and video files via a Bluetooth or USB headset. Some models, called 'watch phones' (or vice versa), have complete functionality of a typical smartphone using LTE technology.
None of these smart watches are necessarily waterproof but they are water-resistant. The Samsung Gear Sport is good to go so long as you don’t go any deeper than 50 meters. Same for the Apple Watch. However, the Q Venture is a little more delicate and can only withstand some splashing and momentary submersion in a meter of water. In other words, the Q Venture will survive if you drop it in a sink full of water and you scoop it out almost instantly.
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. 
Samsung's Galaxy Watch, a Tizen OS watch (starting at $329), is our favorite smartwatch for Android users. In addition to up to four days of battery life and a great design, the Galaxy Watch offers built-in GPS, heart rate sensor, water-resistance, Samsung Pay support, plus a nifty rotating bezel for navigating the interface. You can also download music from Spotify to the watch for offline listening. However, you get far fewer apps than you would with a Wear OS watch.