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.
You can choose from five different watch faces for the Charge 3, making it less customizable than the Ionic or the Versa. Those smartwatches have the advantage of running Fitbit OS, which includes a library of many third-party-developed watch faces. The Charge 3 isn't a smartwatch, so its version of Fitbit's software isn't as robust as what we see on the Ionic and the Versa. It's not as critical for the Charge 3 since it isn't designed to run more than a few basic apps, but those looking for interesting watch faces will have to do with just a handful of options.
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.