There are two different versions of the Gear S2: the standard model on the far left and the Gear S2 Classic, which looks more like a regular timepiece (there's also a slightly bigger and thicker 3G version of the standard Gear S2, which isn't pictured).
Motorola is shipping the 2nd-gen Moto 360 in two different sizes: the 46 mm model is (apart from being a hair thinner) the same size as last year's Moto 360, while the smaller 42 mm version will look a bit subtler on either men's or women's wrists.
All versions of both watches have stainless steel bodies.
Here's one of the reasons we expect the Gear S2 Classic to cost more than the standard model; it jumps from a plastic band to a leather one.
Motorola lets you choose between leather (entry-level) and stainless steel (including several different styles) bands.
Quick release band
Both watches let you easily remove their bands without fiddling with tools and pins.
These are the color options for each watch – the only caveat is that the rose gold Moto 360 is limited to the smaller model.
Fully round display
Surprising some of us, Motorola brought back the "flat tire" display from last year's model.
It's tricky to get an exact area measurement on the Moto 360's oddly-shaped display, but our best estimates put the Gear S2's screen as about 61 percent as big as the larger Moto 360's display.
Based on pixel density, the Gear S2's display is 15 percent sharper than the smaller Moto 360 and 30 percent sharper than the bigger Moto.
Considering how much sense AMOLED displays make on wearables, it's surprising Motorola stuck with an IPS this year.
Both watches give you the option of using always-on clock faces. One thing to keep an eye on in our upcoming reviews, though, will be how battery life differs in both watches when this setting is turned on or off – especially for the Moto's IPS screen (which uses more power than AMOLED when displaying a mostly black clock face).
Similar to the Apple Watch's digital crown, you can twist the Gear S2's bezel to more easily scroll through long menus.
Standalone cellular option
Samsung will offer a Gear S2 with standalone 3G cellular data. This was standard in last year's Gear S, but this year Samsung is offering it as an optional variant – similar to how manufacturers sell tablets.
This year Samsung is (wisely) opening up its smartwatch to non-Samsung Android phones.
Android Wear still has a leg up in compatibility, though, as Google recently added iPhone support to its wearable platform.
According to manufacturer estimates, the Gear S2 will have the longer battery life – though you'll always want to take that with a few grains of salt until we put review units through the paces.
Both watches have built-in wireless charging.
The Gear S2 will support the NFC-based portion of Samsung Pay, but not the Magnetic Secure Transmission (standard credit card reader) portion, meaning retailers will need to have special NFC equipment installed.
The Moto 360 is rated for submersion up to 1 m (3.3 ft) of water, while the Gear S2's IP68 rates it for immersion beyond that depth.
Heart rate sensor
Both watches have heart rate sensors on their backsides.
The Gear S2 has an unspecified dual core processor on the inside, while (like almost every other Android Wear watch) the new Moto 360 runs a Snapdragon 400.
This is standard for most smartwatches right now.
... this too.
Samsung has overhauled its Tizen OS (again) for the new Gear S2, including support for that rotating bezel. App selection was a concern on previous Samsung Gears' Tizen, but we'll see what developers have cooked up when the new watch launches.
The Moto 360 will ship with the latest version of Android Wear.
The Moto 360 will start shipping later this month, while the Gear S2 will launch sometime in October.
Samsung hasn't yet announced pricing for the Gear S2, but we'd be surprised if the Gear S2 Classic didn't ring up for a little more than the standard (plastic-band) model.
The new Moto 360 starts at US$300, and shoots up as high as $430, depending on which size, casing and band options you choose.