The LTE connection will cost you about $10 a month at most carriers, and the LTE model does cost more. There's a non-LTE version, too, if you're not interested in the new feature. Most people probably don't need LTE, frankly, unless you regularly go on hikes or long runs and you don't want to be weighed down with your phone. Still, it's a nice option to have.
Inside the Charge 3 are an accelerometer, gyroscope, optical heart rate monitor, and an SpO2 sensor for tracking blood oxygen levels. The Charge 3 is the third Fitbit device to include an SpO2 sensor, following in the footsteps of both the Fitbit Ionic and the Versa smartwatches. However, currently the SpO2 monitor lies dormant inside all of these devices as Fitbit hasn't made use of it yet.
The company claims that the SpO2 monitor will help its devices look for signs of sleep apnea and other breathing problems, potentially great features for devices that are meant to be worn 24/7. It'll be used primarily in Fitbit's forthcoming Sleep Score Beta, which further analyzes sleep quality using heart rate and breathing data. Starting sometime this November, users with devices that only have heart rate monitors can get a "sleep score" after each night's sleep. Those with an Ionic, Versa, or Charge 3 will presumably have better data thanks to the SpO2 monitor collecting breathing data.

I visited the Fitbit app more than I usually do during the first day of wearing the Charge 3 so I could manage notifications. This device is the first tracker to go beyond the basic call, text, and calendar alerts that most Fitbit trackers can receive. The Charge 3 can alert you to any and all happenings on your smartphone if you want. In the notification panel in the Fitbit app, you can choose which apps you want to receive alerts from—turn on all of them so you never miss a beat, or only turn on the apps that are most important to you.
As far as the number of sports available to track: while it's more of the same, there are some notable exclusions - like golf tracking and open water swimming (pool swimming is a there though). Heart rate monitoring is decent if not class-leading, and it won't keep you waiting around for a GPS signal. There's also all the stress tracking goodies from Garmin's fitness trackers, too. As multi-sport smartwatches go, this is the best in our eyes, and builds on all the good work Garmin did with its previous iterations.
Pebble (watch) was an innovative smartwatch that raised the most money at the time on Kickstarter reaching $10.3 Million between April 12 and May 18, 2012. The watch has a 32-millimetre (1.26 in) 144 × 168 pixel black and white memory LCD using an ultra low-power "transflective LCD" manufactured by Sharp with a backlight, a vibrating motor, a magnetometer, ambient light sensors, and a three-axis accelerometer.[47][48][49][50][51] It can communicate with an Android or iOS device using both Bluetooth 2.1 and Bluetooth 4.0 (Bluetooth Low Energy) using Stonestreet One's Bluetopia+MFi software stack.[52] Bluetooth 4.0 with low energy (LE) support was not initially enabled, but a firmware update in November 2013 enabled it.[53] The watch is charged using a modified USB-cable that attaches magnetically to the watch to maintain water resistance capability.[49] The battery was reported in April 2012 to last seven days.[54] Based on feedback from Kickstarter backers, the developers added water-resistance to the list of features.[55] The Pebble has a waterproof rating of 5 atm, which means it can be submerged down to 40 metres (130 ft) and has been tested in both fresh and salt water, allowing one to shower, dive or swim while wearing the watch.[56]
Garmin, known primarily for its GPS and fitness devices, has taken one step closer to full-featured smartwatches with their Vivoactive 3 Music. This model doesn't run on Wear OS (Google's increasingly-popular OS for wearables), but it does offer thousands of free apps, watch faces, and more via Garmin’s ConnectIQ store. The Vivoactive 3 Music also comes preloaded with 15 sports apps to monitor your progress whether you're running, swimming, lifting, or doing yoga — because, at its core, Garmin is still all about fitness tracking
In 1998, Steve Mann invented, designed, and built the world's first Linux wristwatch,[15] which he presented at IEEE ISSCC2000 on 7 February 2000, where he was named "the father of wearable computing".[16] See also Linux Journal,[17] where Mann's Linux wristwatch appeared on the cover and was the feature article of LJ Issue 75. Seiko launched the Ruputer in Japan - a wristwatch computer with a 3.6 MHz processor. It was not very successful, since instead of a touchscreen it used a joystick-like device to input characters (much like high scores in arcade games), and the small screen with a resolution at 102x64 in 4 greyscales made it hard to read large amounts of text. Outside of Japan, this watch was distributed as the Matsucom onHand PC. Despite the rather low demand, the Matsucom onHand PC was distributed until 2006, making it a smartwatch with a rather long life cycle. Ruputer and onHand PC applications are 100% compatible. This watch is sometimes considered the first smartwatch since it was the first watch to offer graphics display (albeit monochrome) and many 3rd party applications (mostly homebrew).
16GB Capacity/ Supports Voice And Data Over LTE And UMTS/ Built-In GPS And GLONASS/ Dual-Core Processor/ W2 Chip/ Barometric Altimeter/ Heart Rate Sensor/ Accelerometer And Gyroscope/ Water Resistant 50 Meters/ Ion-X Strengthened Glass/ Ceramic Back/ Wi-Fi (802.11b/g/n 2.4GHz)/ Bluetooth 4.2/ Up To 18 Hours Of Battery Life/ WatchOS 4/ Band Fits 140-210mm Wrists/ Space Gray Aluminum Case With Anthracite/Black Nike Sport Band Finish
Apple Watch (1st generation and Series 1) Apple watchOS No 8.2+ (1st generation) 10.0+ (Series 1) Apple S1 (1st generation) Apple S1P 4.0 LE ] From paired iPhone No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes IPX7 Digital 1.7 / 1.5 319x390 / 272x340 AMOLED 1.5 250 / 205 Lithium-ion 42 mm / 38 mm 12.46 / 12.3 36.2 / 32.9 Varies Yes Yes No
At the 2016 Consumer Electronics Show, Razer released the Nabu Watch, a dual-screen smartwatch: integrates an always-on illuminated backlit display, that takes care of some pretty standard features as date and time, and a second OLED screen, which is activated by raising your wrist, allows access to extra smart features.[80] Luxury watchmaker TAG Heuer released TAG Heuer Connected, a smartwatch powered by Android Wear.[81]

You’d be amazed how hard it is to text something as simple as “hi” on many smart watch interfaces. Still, most designs take this into consideration. We tested all kinds of watches from auto-scrolling screens where you drew the letters with your finger to pre-smartphone layouts more akin to the alphanumeric layout of a payphone keypad. While the drawing features were nice, we felt that the texting was a little more manageable on keyboards.