I tested the unlocked Xperia ZL on AT&T's GSM network in New York and was impressed with its call quality. Callers described my voice as crystal-clear with no background noise or audio artifacts to speak of. In fact they had difficulty telling that I was speaking to them on a cellular connection. Voices came through loud and clear through the earpiece on my end as well, and callers' vocal tones were surprisingly rich and warm.
Through the speakerphone, people I spoke to definitely noticed a drop in call quality. They reported a distracting background hiss and said that my voice was muffled. The ZL's speaker does have plenty of volume, though, enough to fill a small office conference room.
Though the Sony Xperia ZL is an unlocked device, it is compatible with a wide range of LTE bands. Specifically it will support LTE bands 1, 2, 4, 5, and 17. As a result I was able to slide in an AT&T SIM card and immediately jump onto the carrier's 4G LTE network in New York.
That's a good thing because I was able to enjoy swift data speeds, with average downloads reaching a high of 30.4Mbps. Average upload speeds were much slower, clocking in at 4.3Mbps.
Perhaps it's because of its big, bright, energy-hungry screen, but I found battery life on the Xperia ZL less than satisfying. I would definitely have to plug the phone in for charging overnight or risk running dry by late evening. Battery testing backed this up, with the Xperia ZL lasting a short 5 hours and 42 minutes on the CNET Labs Video Battery Drain benchmark. That can't hold a candle to the HTC One's longevity of 9 hours and 37 minutes on the same test. Still this result is better than Sony's rated own rated video playback time for the ZL of 5 hours and 30 minutes. The phone also has a battery stamina mode that you can engage to eke out more run time.
If you're familiar with Sony Cyber-shot point-and-shoot cameras, you're well on your way to mastering the Xperia ZL's imaging app. The software boasts a wide range of features, scene modes, and settings, all packaged in an interface ripped right out of the company's compact cameras. With a 13-megapixel sensor and resolution options starting at VGA and topping out at 12 megapixels, the Xperia ZL's camera shoots images of outstanding quality for a smartphone.
Indoors, studio shots were clear, with lifelike colors and crisp detail. The phone's white balance was also spot-on and images were correctly exposed.
Moving outdoors, the Xperia ZL continued to demonstrate its imaging prowess. Details were sharp, and colors in the clothing of pedestrians and foliage vibrant yet not oversaturated. Sony's heavy-handed image processing does tend to paint pictures with an almost cartoonlike flatness, especially if you crop in closely.
Still, the camera app's many features, including modes for panorama and HDR, are welcome inclusions. Where the camera really shines is when taking macro shots up close. If you're into taking a lot of nature close-ups, this is the device for you. My tight shots of flowers had colors that sang and detail on par with what you'd get from more robust point-and-shoot cameras.
There were a few things that gave me pause. The Xperia ZL uses what Sony calls a "Superior auto" mode by default. While it's smart enough to automatically detect and select appropriate scene modes depending on environmental conditions, it demands a lot of processing power. As a result, if Superior auto selects HDR or other scene themes that involve snapping multiple shots in succession, you're likely to get double images of moving subjects. I found that choosing the phone's Normal mode helped fix the issue.
Another weak point in the camera is shot-to-shot time, which was on the slow side. Typically I had to wait about a second between each shot I snapped.
The Sony Xperia ZL has a lot going for it, but its unsubsidized price of $759.99 is high. It sports a sleek and elegant style, if you can forgive the plastic backing, and has both a zippy quad-core processor and support for swift 4G LTE. Those features are compelling, but a better deal in my book is the $649.99 HTC One Developer Edition. For less, the One offers more internal storage, a better screen, and a build quality that can't be matched. Still, I suggest choosing the Xperia ZL over the HTC One if stunning photos and having a local SD card on which to store them are your priorities. A cheaper unlocked Android option is LG's Nexus 4, which costs $299, though it lacks 4G LTE support.