The selection of cross-platform storage tests out there isn't spectacular. PassMark has some basic transfer rate tests, and Basemark has a test painfully labeled "memory" that seems to test storage somehow.
What these tests seem to reveal is decent basic storage performance for the new iPhones, with one curious exception: the iPhone 6 Plus is substantially slower than the iPhone 6, particularly in the PassMark write test. This difference could be related to the fact that our iPhone 6 Plus is a 64GB model, while the iPhone 6 has 128GB of flash. Or it could be related to the rumors that Apple has switched to TLC NAND, which is slower to write data, in at least some new iPhone models.
Neither of those explanations would fully account for the write speed difference entirely, though. Another possibility is that Apple could be using a portion of the NAND array as a fast cache by storing only one bit per cell in it, while the rest of the drive stores three bits per cell in a TLC configuration. Some desktop SSDs do this sort of thing, and the delta between write speeds in the two modes can be large. (The 840 EVO 120GB's SLC writes are rated for 410MB/s, while TLC writes happen at 140MB/s.)
If Apple is using an SLC-TLC caching arrangement, that could explain the numbers above. The size of the single-bit NAND cache is probably larger in 128GB configs. It's possible PassMark overruns the SLC cache in the 64GB config but not in the 128GB one. Also, if the new iPhones do use a one-bit NAND cache, then wow, Apple's storage management is much more sophisticated than I'd expected.
Whatever the case is, it's hard to tell. iFixit's teardowns reveal the iPhone 6 using SanDisk flash, while the 6 Plus uses NAND from Hynix, but both of those parts are 128Gb (16GB) models. Furthermore, Hynix's data sheet lists the part number in the 6 Plus as "E2NAND3.0" without revealing whether it's MLC or TLC NAND. And our software tools are mighty limited on iOS.
Regardless, the 6 Plus 64GB doesn't feel noticeably slower than the iPhone 6 128GB in regular use, even in write-intensive tasks like burst photography or video capture. Both phones are fast and fluid in workloads of that nature.
We tested battery life in four different scenarios. In each case, the phones' display brightness was set to 180 cd/m² before starting, and display auto-brightness features were disabled. Our workload for the web surfing tests was TR Browserbench. The video test involved looped playback of a 1080p video recorded on one of the phones, and our gaming workload was the Unreal Engine-based Epic Citadel demo.
I resisted including our older iPhones in these tests because their batteries have considerable wear and tear by now. That narrows the field somewhat.
Owners of older iPhones will instantly recognize how much of an improvement these results are simply by looking at the number of hours involved. For web browsing and video playback, the new iPhones have essentially all-day battery life. Interestingly, our measured results track pretty closely with Apple's own estimates. For instance, the firm claims "up to 11 hours" of Wi-Fi browsing time for the iPhone 6 and "up to 12 hours" for the 6 Plus.
The real torture test is the gaming workload, where the SoC is working hard throughout. Here, the OnePlus One's run time nosedives to just 2.6 hours, and the iPhone 6 isn't far behind at 3.7 hours. The 6 Plus's larger battery makes it less fragile; the 6 Plus manages over six hours in the gaming test.
These results generally square with my own experience. I've spent weeks using the iPhone 6 Plus as my primary phone, and by habit, I charge it each night. Even with a silly amount of use throughout the day, the 6 Plus's battery meter rarely drops below 40%. That's a massive upgrade from my iPhone 5, which I had to nurse through busy days with periodic charging sessions. I couldn't be happier to see progress on this front, which has been a sore spot in recent years as phones have grown thinner and lighter.
I'm also pleased to see that Apple has added a battery usage meter in Settings that allows the user to see which apps are sucking up battery power. I was surprised to learn, for example, that Google Hangouts was the cause of some battery life woes on my iPhone 5. As newer versions of iOS grant apps more freedom to work in the background and interact, tools like that become more valuable.