The Surface Book is 17 percent taller and 8 percent wider than the Galaxy TabPro S.
The TabPro is thinner, but these measurements are skewed because Samsung's is measured in tablet mode, while the Surface is measured folded over as a laptop. In tablet mode, we measured the Surface Book at 7.14 mm thick, or 13 percent thicker than the TabPro.
The Galaxy TabPro S weighs 35 percent less in tablet mode. We don't yet know exactly what the Galaxy weighs with its keyboard cover attached, but there the discrepancy is going to be much bigger, as the Surface has a traditional (thick and heavy) laptop base compared to the light and thin cover for the TabPro.
The Surface Book has the higher-end build, with its all-metal (magnesium) body. The TabPro has a magnesium frame, but its back is made of plastic.
You'll have two color options to choose from with the Galaxy TabPro S.
The Surface Book has a 27 percent bigger display.
The Surface's display is 24 percent sharper. The TabPro's screen is crisp enough to look good in laptop mode (where it sits farther from your eyes), but pull it closer as a tablet and you're more likely to notice some pixels compared to the Surface Book.
It looks like the TabPro S is going to be the first laptop or 2-in-1 with an AMOLED display launching this year.
We don't know much about the TabPro's active stylus yet, but it sounds like it won't be bundled with the device. The Surface Pen is included in its box.
The Surface Book is primarily a laptop, but you can remove its screen to use as a tablet in short bursts. It does, though, have shorter battery life as tablet than it does as laptop.
The Galaxy Tab is more like the Surface Pro series in that all of its internals are inside the tablet. The keyboard is just a snap-on accessory.
This illustrates just how much less battery you get from the Surface Book when it's in tablet mode.
The Surface Book is a much more powerful device, with either a Core i5 or i7 processor. The TabPro uses a lower-powered (but fanless) Core M chip, with no options for higher-end silicon.
Discrete GPU option
The more expensive Surface Book models include a discrete GPU (Nvidia GeForce) in their base, in addition to the integrated Intel HD 520 graphics that are also in the entry-level models.
The TabPro makes do with lower-end Intel HD 515 graphics.
The Surface Book doubles or quadruples the RAM of the TabPro.
The first two storage tiers are even, but the most expensive Surface Book models shatter the TabPro's 256 GB ceiling.
Samsung gives you the option of going with a cellular-enabled model for the Galaxy TabPro S.
Laptop screen angle
This is a subtle difference you may not think about when making a purchase, but the TabPro is much more limited in angling its screen. It's propped up by its fold-over keyboard cover and only gives you a few angles.
Like any traditional laptop, you can adjust the Surface's screen angle dynamically.
With the TabPro S, Samsung made the same questionable decision that Apple made with its 12-inch MacBook – putting only one USB Type C port on the device. That means charging, data transfer and all USB accessories have to fight for time with that one port. If you buy the TabPro, you'll probably need to add an adapter to your purchase (we don't understand why Samsung didn't just put two USB-C ports on the device).
The Surface has two USB 3.0 ports, as well as a dedicated charging port.
Wired video out solutions are also limited to that USB-C port in the TabPro.
The Surface also adds an SD card, for photographers and those who want to expand their internal storage.
Devices this big don't make much sense as cameras, but you do have that option – and, more importantly, quality webcams for video chat.
Facial recognition login
The Surface can securely log you into Windows just by sitting down and looking at it, using Microsoft's Hello login system.
Neither device has a built-in fingerprint sensor, but if you own a recent Samsung Galaxy flagship, you can use that sensor to log into your Galaxy Tab.
Both 2-in-1s run Windows 10 – either Pro or Home on the Galaxy and Pro on the Surface.
The TabPro S is set to launch globally sometime in February.
It's hard to get a full perspective on the Galaxy TabPro S, as we still don't know what it will cost. We do know that it will include its keyboard cover in the box, but probably not the pen.