The Gear S uses a SIM card for standalone 3G service – so you don't need a phone to be in close proximity. But the Gear S is still a companion device, and to do anything you want it to, will need to pair with a Samsung Galaxy phone, either nearby (via Bluetooth) or long-range (via Wi-Fi and cellular radios).
To use the Apple Watch, you'll need an iPhone (5 or later) to sync up with it. For the Gear S, you'll need a Samsung Galaxy phone (running Android 4.3 or higher) to pair with it.
Apple is branding its iOS-derived Apple Watch software as Watch OS. The Gear S runs a newer (more robust) version of the Tizen software that you'll find on older Gear watches.
Apple has only listed the heights of the Apple Watches, so we're estimating width based on the company's official press images.
The Gear S is anything but subtle, with its huge curved screen dominating the front of your wrist. Its main body measures 38 percent taller than the larger Apple Watch – and 53 percent taller than the 38 mm Apple Watch.
Build (main body)
The Apple Watch's build will vary depending on which edition you buy. The standard Apple Watch has a stainless steel body, the Sport version uses anodized aluminum in its place, while the Edition line is pimped out in 18-karat gold.
The Gear S is all plastic and glass.
All of the band options for the Apple Watch are made of leather, stainless steel or fluoroelastomer (synthetic rubber).
It's too early to say exactly how many color combinations Apple will offer with the Apple Watch. But, with three different lines and many color options within each line, it's going to be many more than the Gear S' two.
Apple hasn't listed the display sizes of the two different Apple Watch sizes, but these are (again) our ballpark estimates. Our figures have them giving you (very roughly) 59 or 45 percent as much area as the Gear S' huge display.
The upside of the Apple Watch's smaller screens is that they're a bit easier to pull off fashion-wise. The obvious upside of the Gear's large screen is that you can use it a bit more like you'd use a smartphone.
Its futuristic design might be a stretch for many shoppers, but the Gear S' curved display is a lot of fun to use. If you've ever used the Gear Fit, then the Gear S is like its bigger, more powerful and more versatile cousin.
We only know that the Apple Watch has a "Retina Display." All that really tells us is that Apple thinks it's sharp and of high quality.
The Gear S has a crisp 300 pixels per inch screen. In person, I thought it looked terrific.
There have been unconfirmed murmurs that the Apple Watch has an AMOLED display. We know for a fact that the Gear S uses one.
The standard and Edition lines of the Apple Watch will have ultra-durable sapphire displays. The Sport line uses Ion-X glass in its place.
We're waiting to confirm with Samsung, but we believe the Gear S uses Gorilla Glass.
One of the more surprising bits from Apple's reveal was the watch's "Force Touch" pressure-sensitive display. It will be able to differentiate a light tap from a full press – and respond accordingly.
It looks like the Apple Watch is going to leave its screen off until you raise your arm (like all the old Samsung Gear watches did).
The Gear S will give you the option of waking it with a gesture or – for the first time in a Tizen watch – have an always-on clock face.
Both watches have touch screens and built-in voice control. But Apple is adding another dimension with its "Digital Crown" winder.
While winders on old-school watches kept them ticking and adjusted the time, the Apple Watch's version lets you zoom in and out. The idea is that pinch/zoom gestures aren't a good fit for such a tiny screen, so it fills that hole.
The Gear S doesn't have a winder, but its screen is big enough that finger pinching and spreading gestures should work just fine.
Speaking of voice control, we're looking at Siri vs. S Voice. Siri is much faster in iOS 8, and I imagine it will have the advantage here – possibly by a wide margin. But during our brief hands-on time at Samsung's event, the Gear S' S Voice did appear to be improved over the version that you'll find in older Gears.
We're looking at two buttons on the side of the Apple Watch (the winder doubles as a second button) and a lone home/power button on the front of the Gear S.
The Apple Watch is reportedly only protected against splashes (or perhaps some rain). The Gear S' IP67 rating means it can soak in 1 m (3.3 ft) of water for 30 minutes, and live to tell the tale.
Both watches let you take and make calls on your watch.
The Gear S I played with in Samsung's demo area also let you make calls directly from the watch's SIM card, but Samsung says that this may or may not be a feature in the shipping version. I wouldn't be surprised if some of those details varied from carrier to carrier.
If the Apple Watch is trying to be the iPhone of smartwatches, then the Gear S is more like the wearable Galaxy Note. Much like Samsung's phablet, the Gear S' huge screen could have some drawbacks (mostly on a fashion level) – but also some advantages.
One of the biggest advantages is its virtual keyboard, which lets you quickly rap out text messages and emails. A 2-in screen makes for a relatively small keyboard, but I found its auto-correct to make typing quick and easy.
The Gear S will also support third-party keyboards.
The Apple Watch is going to work with Apple Pay terminals, which will start popping up later this year. Though Android phones have supported NFC payment services for years (none of which have been very successful), the Gear S doesn't support any of them.
Heart rate sensor
Both watches have built-in heart rate sensors. Apple's also has a feature that lets you "send" your heartbeat to a friend or loved one. It might end up being gimmicky, but I could also see it helping to create a sense of intimacy – even if your partner is on the other side of the world.
Similar to the heartbeat-sharing feature, the Apple Watch lets you send little taps to friends, family or loved ones that are also wearing Apple Watches. Tap your display, and your partner will feel it on his or her Apple Watch.
Digital Touch also includes things like drawing on your screen, creating emojis or using your Apple Watch as a walkie-talkie.
Both watches have built-in fitness tracking. Apple's is baked into Watch OS, showing your daily stats in the form of three rings (movement, exercise and standing).
The Gear S ships with a Nike+ running app.
Samsung reps weren't saying anything about battery life during my hands-on time, but the press release mentions a two-day estimate with typical use.
Apple has been mum on the Apple Watch's uptimes and battery capacity.
The Apple Watch will display navigation from your paired iPhone, including different vibrations to indicate different turning directions.
The Gear S has its own GPS radio (no need to leech that from your smartphone), using Nokia's Here for directions. The GPS also integrates into the Gear's Nike+ workout app, for tracking your routes.
Standalone music player
If you leave your phone behind for a workout, both watches let you store some music on the watch – and listen via paired Bluetooth headphones.
The Apple Watch launches in April of 2015. The Gear releases in late October. Samsung also announced that the four major US carriers will start selling it sometime this (Northern) Fall.
The minimum that the Apple Watch will set you back is US$350, for the aluminum Sport version. The stainless steel Apple Watch starts at $550, and the 18-kt gold Edition watch starts at – gasp – $10,000.
The Gear S varies a bit from carrier to carrier, but typically rings up for around $300. Carriers also offer contract and installment plan pricing.