If you're looking for a smartwatch, chances are these two will be on your radar.

Samsung's Gear S3 Frontier has been around for a few months, but it's still fresh in everyone's mind as Samsung's top-end wearable offering. Coming in just a tad later, The big and fully featured LG Watch Sport was a launch device for Android Wear 2.0 and matches the Gear S3 in more ways than one.

Both of these smartwatches are big, feature-packed and relatively expensive. So which one should you consider strapping to your wrist? Let us help you decide.

See Gear S3 Frontier at Amazon
See LG Watch Sport at AT&T

Hardware and design

Right from the start, these watches alienate a large portion of the potential market with their size. The LG Watch Sport's case measures in at a very large 45.4 x 51.2 mm, while the Gear S3 has nearly the same footprint at 46 x 49 mm. The Watch Sport is incredibly thick at 14.2 mm, and the Gear S3 Frontier is 12.9 mm — svelte by comparison, but still large. With dimensions like that, neither of these watches will fit on smaller wrists, and even those with a wrist that can hold such a large watch may not be a fan of the size — the thickness, in particular, can be an issue on either watch when it comes to fitting underneath a sleeve.

Two huge, rugged watches with different overall looks.

The only thing to really differentiate the two is their external styling. The Gear S3 Frontier follows its name well with a rugged design that seems like it'd be at home in the woods or on a trail. Its dark metal exterior, large gnarled bezel and textured buttons give off a masculine look that's definitely popular nowadays. Despite the "Sport" name, the LG Watch Sport is relatively tame by comparison. Its body is entirely smooth, lightly brushed metal that can fit with a wider variety of clothing but lacks a strong identity.

More: Our complete LG Watch Sport review!

Part of that identity on the Gear S3 is in its very nice rubber bands, which feel better than the LG Watch Sport's. Further, the lug design on the Gear S3 gives the bands flexibility at their mounting point, which is more comfortable than the integrated bands on the Watch Sport. To complete the trifecta of wins, Samsung's smartwatch lets you swap out the Gear S3's bands for any 22mm bands you can find, giving you customization options down the road.

For its size, the LG Watch Sport does manage to give you more screen with a 1.38-inch display compared to the Gear S3's 1.3-inch. That may not seem like a ton, but extra room is always welcomed on a (relatively) small device — especially when you're getting it in the basically the same case size as the Gear S3. LG's display is also higher resolution at 480x480 versus 360x360, though both displays offer automatic brightness and look great.

Software and experience

LG Watch Sport vs. Samsung Gear S3

The differences here are bigger than the hardware styling of these two watches — starting, of course, with the different platforms. The LG Watch Sport has Google's latest Android Wear 2.0 software, while the Gear S3 has Samsung's own Tizen Wearable OS platform that is a small iteration from what we saw on the Gear S2.

Android Wear 2.0 gets the basics right, and has great watch faces.

Android Wear 2.0 a big step up in usability and functionality from previous iterations, focusing on feature-filled watch faces and manageable notifications. The API-based watch face complication setup on Android Wear 2.0 lets any watch face developer make great-looking dials that also integrate with any app on your watch designed for complications, and notifications are perfectly linked with your phone for a seamless experience. Though it can do more, Android Wear 2.0 really nails these basics.

More: Our complete Samsung Gear S3 review!

Tizen on the Gear S3 can be configured to be simple, but in general requires a bit more interaction with the watch in order to get the same tasks done. Some app notifications don't play nice with the Gear S3, and while Samsung's store has many great watch faces (plus the solid default set) it doesn't have the same catalogue or potential of the Google Play Store. The same goes for installing apps directly on either watch, though both platforms hit the few big names you'd actually want to install on your watch so that's a basically a wash.

You get all of the core specs and features — now pick a platform to get locked in to.

More important are the built-in features both watches offer — and with hardware this big, it shouldn't be surprising that you get all of the bells and whistles on both. With either choice you're getting a capable processor, 4GB of storage, big battery, GPS, Bluetooth, NFC, IP68 water and dust resistance, heart rate monitoring and optional LTE connectivity. The Gear S3's rotating bezel matches the LG Watch Sport's rotating crown for non-touch input, and both give you a great way to get through the software on a daily basis. In my time with both watches the Gear S3 can offer better battery life, somewhere in the realm of 50-75% better than the Watch Sport, but chances are you'll be charging both nightly anyway.

The only real question here is ecosystem lock-in for two big features: fitness tracking and mobile payments. The Gear S3 has S Health and Samsung Pay, while the LG Watch Sport gives you Google Fit and Android Pay. As far as payments go, the Gear S3 takes the advantage with MST technology that lets you pay anywhere a card can swipe. The fitness point may not be as big of a deal as you'd initially think, as you'll be able to find big names like Endomondo, Map My Run, MyFitnessPal, Strava, Runtastic, RunKeeper and more (be sure to check compatibility before you choose) but daily tracking is still best handled by S Health and Google Fit.

Bottom line: Very similar smartwatches

The LG Watch Sport and Samsung Gear S3 Frontier have far more in common than you may think considering their different manufacturers and platforms. If you're considering these watches, you've already decided that you can manage their large sizes. You're also seeing value in a huge list of specs and hardware features that are shared between the two. It just comes down to which one you like the external design of more, and what platform you want to integrate with.

The Gear S3's dark, rugged design with removable bands may speak to you more than the Watch Sport's basic look and extra thickness with fixed bands. When you go with Android Wear on the LG Watch Sport, you're going to see smoother integration with your Android phone and all of Google's services, while the Gear S3 offers Samsung Pay and has a higher ceiling in terms of watch-only functionality.

Both watches charge the same $349 price and set the bar in many ways for what we want from a smartwatch today. Either one is a great choice if you don't feel strongly about one platform or the other, so make your pick based on the design and few exclusive features that appeal to you most.

See Gear S3 Frontier at Amazon
See LG Watch Sport at AT&T