The Tab S3 is the more compact and portable of the two. When held in landscape orientation, the Surface Pro 4 is about 18-percent wider and about 16-percent taller. It's also about 29-percent thicker.
There's a considerable difference in weight as well, even without their respective keyboard accessories. The lightest Surface Pro is 44-percent heavier than the lightest Tab.
The Tab S3 has an aluminum frame and a glass back panel. The Surface Pro 4 has Microsoft's characteristic magnesium alloy build.
The Surface is only available in silver, but the Tab comes in a black option as well.
The 9.7-inch Tab S3 is smaller and has a boxier 4:3 aspect ratio. The 12.3-inch Surface Pro offers 27-percent more display area, with a 3:2 aspect ratio.
The Surface's screen packs in slightly more pixels, but since the Galaxy Tab S3 supports HDR, it could have a larger color gamut and higher fidelity in light and dark areas.
The Tab S3 has four speakers, which are meant to offer a better listening experience across different viewing orientations.
The Tab S3 has a built-in fingerprint sensor. The Surface Pro 4 works with Windows Hello's facial recognition features, so you can login just by showing your face. There's also a keyboard cover option with a fingerprint sensor built in.
Only the Tab S3 is available in a Wi-Fi + LTE variant (or at least it will be at some point in the future).
Both of these tablets can be outfitted with keyboards to turn them into more capable laptop stand-ins. Both keyboards are sold separately with a US$130 price tag.
If you look closely, you'll notice a few differences. The Microsoft type cover has a glass trackpad, while the Samsung option does not. The Samsung option also is used to prop up the tablet, while the Surface Pro has a built-in kickstand that adjusts dynamically in a variety of angles.
Both options support active stylus input. The Tab S3's S Pen stylus is included in the box, and has the advantage of being battery-free and never needing charging. The Surface Pro includes a Surface Pen (though it is possible to buy one without it, so pay attention if you make a purchase) which takes one AAAA battery.
The Tab S3 has a USB Type C charging/data port, while the Surface Pro has a dedicated Surface Connect charger.
Additional I/O ports
The Surface Pro 4 does have a USB 3.0 (legacy) port, as well as a mini DisplayPort.
The Tab S3 has a capable Snapdragon 820 mobile processor. The Surface Pro contains sixth-generation Intel core m3, i5 or i7 chips.
Like most mobile devices, the Tab S3 does not offer varying levels of RAM. But with the Surface Pro 4, you can opt for 4 GB, 8 GB or 16 GB.
Again, the Tab S3 is only available in one 32 GB option. The Surface Pro offers four storage tiers between 128 GB and 1 TB.
On the plus side, both support expandable storage via microSD.
We don't expect anyone to rely too heavily on their tablet to take photos, but the Samsung option does have a sharper rear camera. As far as selfies and video conferencing goes, their front cameras are evenly matched at 5 MP.
If manufacturers' estimates are to be believed, the Tab S3 should have slightly more staying power. Of course, battery life can vary dramatically according to use.
The Tab S3 runs Android Nougat with Samsung's TouchWiz UI layered on top, while the Surface Pro 4 runs Windows 10 desktop software. That means the Surface Pro is a better choice for most professional applications, though it's possible for the Tab S3 could give it a run for its money in a few areas. (Microsoft Office, for example, has a capable and similar mobile version for Android.)
You can multitask on both of these, but not quite in the same way. Since the Surface Pro runs desktop software, it lets you multitask with multiple windows just like any other laptop would. The Tab S3, however, is limited to the comparatively hobbled split-screen multitasking (which doesn't work with all apps) that Android has to offer.
The Surface Pro 4 has been around since October 2015 – it's ripe for an update, which we expect to see sometime this year. The newly announced Tab S3 hits shelves on March 24.
Starting price (tablet and keyboard)
These prices are for fully equipped machines – they include the tablet plus an entry-level keyboard accessory. The Tab S3 bundle will cost about $730 – $600 for the tablet plus $130 for the keyboard. The Surface Pro 4 bundle ($729 plus $130) starts at about $200 more altogether, but since it's an older release, it may be possible to find it for less.
The price difference is probably justifiable to those who need a desktop software experience, but for light use and recreational activities, the cheaper-but-still-premium Samsung could deliver.
For more info, check out our review of the Microsoft Surface Pro 4 and our hands-on with the Samsung Galaxy Tab S3. If you're willing to wait a little longer before making a purchase, you may want to wait for Samsung to confirm price and release date for the Tab S3's Windows-running cousin, the Samsung Galaxy Book, which is shaping up to be even more comparable to the Surface Pro 4.