Update: You can now read our hands-on comparison of these two handsets.
Despite having a smaller screen, the iPhone 6 Plus is 3 percent longer than the Galaxy Note 4.
The iPhone 6 Plus isn't as thin as its little brother, the iPhone 6, but it is still 13 percent thinner than the Note 4.
The iPhone 6 Plus is just 2 percent lighter than the Note 4.
In terms of premium build quality, there's no contest here. The iPhone 6 Plus has a smooth aluminum unibody build, taking some design cues from the latest (two-year-old) iPod touch. The Note 4, though comfortable to hold, is made of a faux leather plastic.
The Note 4 does, however, have a metal band running around its edge. In previous Samsung devices, that band was a metallic-looking plastic.
We're looking at three color options for the iPhone 6 Plus and four for the Note 4.
The iPhone 6 Plus is unquestionably a phablet, but its screen size hasn't quite caught up with Samsung's. The Note 4 gives you 7 percent more screen than the iPhone does.
This is the first 1080p iPhone, and it should look noticeably sharper than the 750p iPhone 6.
If you want pixels, though, the Note 4 is the place to go. It has a Quad HD display that packs in 78 percent more pixels than the iPhone 6 Plus does.
The iPhone's 1080p is going to be more than sharp enough for most people, but my eyes do enjoy the insane pixel density that you get from Quad HD displays.
We're looking at an IPS panel in the iPhone, next to Super AMOLED for the Note 4. The latter always has blacker blacks and typically has higher contrast and richer colors ... but we'll need to put the iPhone 6 Plus through the paces before jumping to conclusions.
These two have a lot in common, but this might be the biggest point of difference. Though you can swipe and tap the Note's screen with your finger, the Galaxy Note experience centers around Samsung's stylus, the S Pen.
Samsung says that this newest S Pen has double the pressure sensitivity of the one we saw in the Note 3.
Both phablets have fingerprint sensors, but the iPhone's Touch ID is more convenient. With it, you simply rest your finger on the home button for a brief moment. Samsung's sensor requires you to swipe your finger and, at least on the Galaxy S5, I often have to do it a couple times before it registers.
The two latest iPhones are the first to carry NFC chips. That's nothing new for Android handsets like the Galaxy Note 4.
While services like Google Wallet and Soft Card (formerly Isis) have been trying to establish NFC-based tap-and-pay payments for years, to say they haven't set the world on fire would be a vast understatement.
So while Apple Pay is hardly the first player in the NFC payments game, it could be the first to take off. The popularity of the iPhone combined with some clever marketing and leverage with retailers could be the secret sauce that the technology has been missing.
We'll have to put these two through the paces before we have much to say about their respective uptimes.
Ultra Power Saving Mode
This may be the most innovative software feature Samsung has created. Ultra Power Saving Mode can prevent your Note 4 from running out of juice when things are getting tight. It basically turns your device into a multitouch feature phone, with only the bare essential apps and services available, but can stretch 10 percent juice into 24 hours of battery life.
The Note 4 also has a fast charging feature, that can juice your phablet from 0 to 50 percent in "about half an hour."
Here's another category where we'll need to wait for some hands-on time before we say much of anything. It does look like the Note 4's rear camera use a similar (if not the same) sensor to the one we saw in the Galaxy S5, though, so it should be quite good.
Apart from size and number of pixels, this is one of the few differences between the iPhones 6 and 6 Plus. This larger model has Optical Image Stabilization, to help cut down on the effects of shaky hands. The Note 4 uses this technology as well.
Heart rate sensor
The Note 4, like the Galaxy S5, also has a heart rate sensor on its backside. The iPhone can use third-party apps that achieve a similar (though less elegant and, likely, less accurate) end by using the phone's camera and flash.
It's a little surprising that Apple didn't add a side-by-side multitasking mode to the large-screen iPhone 6 Plus. Samsung's Note line has offered the feature for several generations now.
Samsung's Multi Window is a handy feature, and it should be a bit easier to remember now that it's tied to the Note's Recent Apps button. But its Achilles' heel is that it's only compatible with a select group of apps.
This is an important software feature to have on a phablet. With all of that screen, you can lose the ability to reach everything while using the device with one hand. Both of these phablets have software-based workarounds.
On the iPhone, Apple lets you slide the top of the screen down to the bottom by double-tapping the home button. This ignores the issue of typing with one hand, but it should help out in most other cases.
On the Note 4, a gesture shrinks the entire screen down to a manageable one-handed size. This has the advantage of shrinking the keyboard as well.
Storage options are mixed, with the iPhone starting lower, but maxing out with a more spacious 128 GB option.
The Note 4 can help to make up for that, though, with its microSD card slot.
It's too early to have much to say about the new iPhones' A8 chip, but it goes up against the zippy Snapdragon 805.
The LTE version of the Note 4 gets the Snapdragon 805 listed above, but the HSPA version will have an octa-core Samsung Exynos CPU in its place.
We don't yet know how much RAM is in the iPhone 6 Plus, but it will almost certainly be either 1 GB or 2 GB.
Like many recent Android flagships, the Note 4 has a built-in IR blaster, letting you control your TV (and cable/satellite box) with your device.
If you want to step into the Matrix, then the Note 4 can help. It's the only device that's compatible with Samsung's new Gear VR headset.
There are other smartwatches that are compatible with each platform, but these are the most popular choices.
A recent iPhone, like the 6 Plus, will be required for using the upcoming Apple Watch, while Android handsets like the Note 4 are needed to pair with Android Wear watches (like the Moto 360). The Note 4 also plays nicely with Samsung's line of Gear watches.
The iPhone 6 Plus launches along with the iPhone 6 on September 19. The Note 4 will launch in the US on October 17.
Starting price (off-contract)
We don't yet know what the Note's full retail price will be, but I'd bet on it starting at the same US$700 that we saw for the last two Galaxy Notes.
Starting price (on-contract)
The Note's on-contract price (more common in the US) is also a mystery, but I'd be surprised if it didn't hit the same $300 starting price as the iPhone 6 Plus.
These are almost guaranteed to be the two most popular phablets this shopping season, and we'll have much more to come. In the meantime, you can delve into our full reviews of the Galaxy Note 4 and iPhone 6 Plus.
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