Huawei has once again teamed up with famed camera maker Leica to "co-engineer" its imaging system. Like the Huawei P9 that was unveiled in April, the Mate 9 has a dual-lens system on its rear that's similar to the iPhone 7 Plus. One sensor captures 12-megapixel RGB data while the other records 20-megapixel monochrome information. Together, they're supposed to deliver rich colors and fine details.

I was generally happy with the pictures I took; they were typically sharp though often overexposed. They also generally lacked the vivid colors you'd get from, say, the Galaxy S7 or one of the Google Pixels. Photos taken with the Mate 9 in low light were also grainier than what I got from the other two handsets. As on previous devices, Huawei is offering a Night Shot mode that's supposed to take better images in the dark, thanks to longer exposure. This starts a 10- to 17-second recording session, during which any movement of phone blurs the scene. You'd either have to use a tripod, or sit extremely still for your photos to come out clean.

Still, thanks to a wide aperture mode on the camera, you'll be able to achieve a pleasant depth-of-field effect on your shots. Though the rear lenses have fixed apertures of f/2.2, you can play with the software setting here to make it seem wider than that. The feature is also easy to enable and disable; a tap of the aperture icon on top of the viewfinder turns it on and off. This effect works well on pictures of people or food, but slows down the capture of landscapes as the camera struggles to find a foreground to keep in focus.

An example of wide aperture mode applied with maximum blur.

The nice thing about Huawei's implementation here compared to Apple and Samsung's is that the Mate 9 lets you decide how much blur you want before you take the shot. You can drag a slider on the screen to choose just how much background you want out of focus. Samsung's All Focus tool only lets you do that after you take the picture, while Apple's tool doesn't let you customize the level of intensity.

Unfortunately, wide aperture mode does not extend to the front camera, where it would have made my selfies pop. Still, the 8-megapixel front camera captured sharp images with mostly accurate colors. Sometimes, when shooting indoors and with Beauty Mode activated, the Mate 9 tended to overexpose, resulting in garishly colored lips and excessive contrast. At its default setting of five on a scale of one to ten, Beauty Mode made people look artificial, with the rest of the image appearing blown out, to boot. Dialing down to level three and below alleviated the problem though.

Overall, the Mate 9's cameras are capable of capturing decent photos that are clear and colorful, and that wide aperture mode is nifty, but they won't impress you like the iPhone 7 Plus or Google Pixel will.

Performance and battery life

In a sea of phones powered by Qualcomm's mobile processors, the Mate 9 stands out for using Huawei's octa-core Kirin 960 processor. This allows the company to tweak both hardware and software to offer some extra features, like that Machine Learning Algorithm I mentioned, which promises smoother and more responsive performance. In other words, the Mate 9 will learn your behavior over time and optimize performance so it appears faster to you.

Say, for example, you habitually open Instagram right after you close Twitter. The algorithm will remember your behavior and eventually start diverting resources like part of its 4GB of RAM to prepare Instagram the next time you have Twitter open.

During my time testing the Mate 9, the set of actions I performed the most were launching the Gallery app right after closing the camera, as well as checking a battery drain application after looping a video on MX Player. The thing is, I couldn't really tell if the overall smoothness I experienced on the Mate 9 was due to artificial intelligence or simply thanks to a relatively new, speedy processor. It's not as if there's a way for me to A/B test that. Jumping from app to app was a lag-free experience, and I noticed no difference in smoothness whether I was opening programs I had previously used or those that I had never launched. I ran a screen recording app while loading up a game and scrolling up and down repeatedly on Engadget's page on Chrome, and didn't encounter a hiccup.

Huawei Mate 9 Google Pixel Google Pixel XL Samsung Galaxy S7 Edge HTC 10 AndEBench Pro 15,424 14,941 16,164 13,030 16,673 Vellamo 3.0 7,207 5,343 5,800 4,152 4,876 3DMark IS Unlimited 28,139 28,645 29,360 26,666 26,747 GFXBench 3.0 1080p Manhattan Offscreen (fps) 30 46 48 47 48 CF-Bench 64,154 30,997 39,918 46,290 49,891

The Mate 9's performance on synthetic benchmarks puts it in the same league as leading flagships like the Google Pixel and the Galaxy S7. It beat competing phones, including both versions of the Pixel, the Galaxy S7 Edge and the HTC 10, on the browser-based Vellamo but lost to the Pixel XL and the HTC 10 on AndEBench. The Mate 9 didn't fare as well on graphics-intensive tests, falling behind the two Pixels on 3DMark Ice Storm Unlimited. Even then, the gap wasn't huge. The Mate 9 still outperformed the Samsung and HTC devices on that test too.

All of that horsepower is matched by a generous 4,000mAh battery, which Huawei promises will provide 20 hours of continuous video playback. On Engadget's rundown test, which involves looping an HD video with the brightness set to 50 percent, the Mate 9 lasted an impressive 14 hours and 34 minutes. That's 20 minutes longer than the Pixel XL, one hour longer than the Galaxy, and a whopping two hours more than the Pixel.

In the real world, that longevity meant I barely had to recharge the Mate 9 (except after battery tests) during my review period. After I left the phone in my purse for two days without using it, I was pleasantly surprised to find that it still retained 80 percent of its power. On a typical workday, too, during which I received notifications throughout the day, snapped a bunch of pictures and uploaded dozens of images to my Google Drive, it sipped power at a slow rate. At the end of the day, the battery life rating had dipped from 57 percent at the start of the day to 36 percent in the evening.

When it did need recharging, the Mate 9 got back up to 55 percent within an hour of being plugged in, thanks to Huawei's SuperCharge technology. That's fast, considering how large the battery is and how long 55 percent can last. Getting through the first 10 percent was slower, though; it took about 20 minutes to fill up.

In case you were worried that squeezing a big battery into a thin frame could make the phone susceptible to exploding (as was reportedly what happened with the Samsung Galaxy Note 7), Huawei promises its battery is safe. The company says it uses a five-gate protection system that monitors real-time temperature, voltage and current to "eliminate safety hazards and safeguard battery life." Indeed, during my testing, the Mate 9 never got too warm, even during resource-intensive tasks.

The competition

It's hard to find comparisons for the Mate 9 when we don't yet know how much it'll cost or when it will launch in the US, but perhaps we'll find out at Huawei's CES press conference early next month. But based on its European pricing (€699 or about $752), it looks like the Huawei phone will go up against the Google Pixel XL ($769 and up) and the Samsung Galaxy S7 Edge (north of $760 through most carriers).

While both the Pixel XL and the S7 Edge offer ample, 5.5-inch screens, the Mate 9's roomier 5.9-inch panel will appeal to those who need even more real estate to for easier reading, gaming or multitasking. The Mate 9 also has the longest endurance of the lot.

However, both the Pixel and the Galaxy have much better cameras than the Mate 9, while the Pixel in particular runs a cleaner version of Nougat, making it the best choice for Android purists.

Wrap-up

Ultimately, what sets the Huawei Mate 9 apart is its large screen and excellent battery life. Although the company has been touting its machine-learning algorithm, it's something that you won't notice or think about unless performance starts to suffer. Either way, the Mate 9 is a perfectly capable device. That said, photography aficionados and stock-Android fans will still prefer the Pixel. Instead, the Mate 9 will mostly appeal to those who want a large canvas to watch videos or play games in a phone that's not too hefty. If the handset's US price is close to what it costs in Europe, it could be a slightly more affordable option than some rivals, making it a good value for the performance it delivers.