Both tablets have the same killer feature: they're ridiculously thin. The iPad Air 2 comes out ahead, though, by 8 percent.
The Galaxy Tab S 10.5 is a slightly larger tablet all around. It's 3 percent longer and 4 percent wider.
We'll say the same thing for weight that we did for thinness: they're both sitting at a very nice extreme. In this case, the iPad comes out a bit ahead too. It's 6 percent lighter.
You get higher-end build materials with the iPad, as the Galaxy Tab is made of plastic. But at least the Tab's dimpled finish is comfortable in hand.
This year's iPads are the first to offer a gold color option.
If you want maximum screen area, then the Tab S gives you almost 10 percent more than the iPad does.
You'll also want to note the two different aspect ratios. The iPad's 4:3 is more boxy (great in portrait and landscape), while the Tab S' 16:10 is more elongated (better for landscape).
Both tablets have stunning displays, but the Tab's is 9 percent sharper. There's no reason to steer clear of the iPad's screen quality, though. It's terrific.
The iPad uses an IPS screen, while the Galaxy Tab's is an AMOLED. AMOLED screens have blacker blacks, rich colors and great contrast. The iPad is more than holding its own in those areas too.
Apple put an anti-reflective coating on the iPad Air 2's display, which can reduce glare by 56 percent. I've tested it, and it's a noticeable improvement when reading outdoors.
Both tablets have fingerprint sensor home buttons, but the iPad's is quicker and easier to use. You simply rest your finger on the Touch ID sensor for a moment, while you have to swipe your finger over Samsung's sensor.
With iOS 8, Touch ID is now compatible with select third-party apps (password managers are a perfect fit). The Galaxy Tab's sensor also plays nicely with third-party apps (including PayPal), but its selection isn't as wide.
Both tablets start with a base 16 GB of internal storage, but the iPad doubles the Tab's storage on the second tier. The iPad also maxes out higher, with 128 GB.
The Galaxy Tab can help make up for that, though, with support for microSD cards.
Both tablets have good battery life, and should be all-day tablets for all but the heaviest power users (or power Candy Crush players).
Ultra Power Saving Mode
This makes much more sense on a phone than it does a tablet, but you'll find Samsung's Ultra Power Saving Mode on the Tab S. It lets you keep your tablet on the grid by limiting available apps and turning its home screen black & white.
Both have unusually good cameras (well, for tablets). The iPad's even includes the iPhone's excellent slow-motion video recording mode.
If you looked at cores and clock speeds alone, you'd probably assume the Galaxy Tab were the faster device. Not so. In benchmark app Geekbench 3, the iPad scores about 66 percent higher in multi-core and around 104 percent higher in the single-core test.
Both tablets are very zippy in day-to-day experience, but the iPad has the raw performance advantage. I'd say it also feels a bit smoother overall.
Note that this graphic only shows the processor for the Wi-Fi only Tab S. The LTE version has a Snapdragon 800 in its place.
The iPad Air 2 is the first iPad with 2 GB of RAM, but the Galaxy Tab still has a leg up on it.
That extra RAM comes in handy with Samsung's Multi Window mode, which lets you run two apps on the screen at the same time. You'll want to note, though, that only select apps are compatible.
Call & text forwarding
With Apple's Continuity and Samsung's SideSync 3.0, you can receive calls and texts on either tablet (forwarded from a paired phone). The iOS version is farther-reaching, though: it works with any iPhone running iOS 8. The Galaxy Tab's version requires a Galaxy S5.
The Galaxy Tab's phone syncing does, however, have some extra tricks up its sleeve. It lets you control a paired Galaxy phone from the tablet (its screen pops up in a little phone-sized window).
The iPad Air 2 is still hot off the press, while the Tab S launched this past July.
Pricing starts at the same US$500. If you keep your eyes open, though, you might find some sales on the three-month-old Tab S.