The Galaxy S6 and its curved sibling, the Galaxy S6 edge, are both a little bigger than the new iPhone: the GS6 is 4 percent taller and 6 percent wider, while the GS6 edge is 3 percent taller and 4 percent wider.
The iPhone 6s is a bit thicker than last year's iPhone 6. That has the 6s measuring 4 percent thicker than the Galaxy S6 and just a hair thicker than the S6 Edge. Just remember that, relatively speaking, all three are very thin phones.
The iPhone 6s also measures 4 percent heavier than the GS6 and 8 percent heavier than the Edge. Like with thickness, though, those are still pretty minor differences.
No chintzy builds here: you get a premium aluminum design on the iPhone and a premium Gorilla Glass 4 backing on the Galaxy S6 pair.
... and, just a heads' up, for the categories where we show the Galaxy S6 without also showing the Edge, there aren't any differences between Samsung's two flagships.
The unibody iPhone's aluminum backing wraps around to its sides, while the Galaxy S6's glass makes way for aluminum on its frame.
As an "S"-year upgrade, the iPhone 6s sticks with the same display size we saw in last year's iPhone 6. That means the two Galaxy S6 phones still give you 18 percent more real estate.
The screens of the ultra-crisp GS6 pair come out 77 percent sharper, based on pixel density.
Nothing has changed here; we're looking at IPS vs. AMOLED.
"3D Touch" display
One of the iPhone 6s' big selling features is its new 3D Touch display. It takes the pressure-sensitive Force Touch we saw on the Apple Watch and latest MacBooks, and adds a third level of interaction: the screen will differentiate among a tap, regular press and deeper press.
At first glance, that might not sound like something you need on your phone. But Apple's examples of how it's implemented sound like it could be an innovative feature.
In some areas of iOS, a regular (first-level) press on the screen will give you what Apple calls a "Peek": a quick pop-up preview (for things like emails, website links and photo thumbnails).
... if that Peek was all you needed, then a lift of your finger would take you back to wherever you were (like your inbox, a web page or the camera app).
But if you wanted a deeper look at the pop-up content you just previewed, continue pressing harder into a "Pop": a full-screen view of the content.
This all sounds a little complex for the historically simple iOS, but it has the potential to let you do more within the confines of multitouch.
Both handsets have excellent, touch-based fingerprint sensors.
Apple and Samsung each have their own mobile payment services, but Samsung Pay (when it launches later this month) should automatically have the retailer adoption advantage on Day One. Unlike the NFC-based Apple Pay, Samsung's service will work with most standard credit card readers.
No searching of a short list of early adopter retailers necessary. If they have credit card machines that don't require you to hand your card to the clerk, then they should be covered.
Apple hasn't announced the cores and clock speed for the A9 system-on-a-chip in the new iPhones. But no matter what they ultimately show up as in benchmarks and teardowns, history has taught us that you'd be foolish to draw any conclusions about the iPhone's overall performance from those numbers alone.
In other words, iPhone performance has always transcended what you'd expect from raw specs.
Ditto for RAM; Apple doesn't typically announce these details.
The Galaxy S6 gives you more storage on the entry-level tier, but it all evens out from there.
This is the iPhone's first rear camera resolution bump since the 4s in late 2011.
Camera aperture (rear)
Though the new iPhone's camera should be an improvement over the (already great) shooter in last year's iPhone 6, the new model's aperture stands pat at ƒ/2.2.
Like with last year's iPhones, only the bigger model (iPhone 6s Plus) gets Optical Image Stabilization.
Physical camera shortcut
Double-tapping the Galaxy S6's home button to launch its camera might sound like a minor feature. But in the pair of GS6 flagships, we found that it makes it super-easy (and super-quick) to snap shots.
Though Apple has no physical button shortcuts dedicated to the camera, it does use 3D Touch to let you press the Camera app's home screen icon to jump right into a selfie, video, slow-mo video or regular shot.
This isn't technically official, but a shot of the iPhone 6s' internals in an Apple-made promo video (spotted by MacRumors) appears to confirm that the phone has a 1,715 mAh battery.
Apple hasn't jumped into wireless charging for its mobile devices just yet.
Like plenty of Android flagships from the last year, the GS6 has a fast-charging feature that will juice up your phone faster than on other phones.
iPhone 6s and 6s Plus pre-orders start at the end of this week, with the phones hitting stores on September 25.
Starting price (full retail)
These figures for the Galaxy S6 are ballparks, as US carriers vary a bit on their full retail pricing. No matter how you slice it, though, the recently-discounted Galaxy S6 is the cheapest of the three.
... just remember that, for all three handsets, most shoppers will either pay with an installment plan or sign a two-year contract to avoid paying these prices upfront.