At least in the US, Sony has yet to create a blockbuster smartphone on par with the Samsung Galaxy S4 or Google Nexus 5. With the Xperia Z1S, its latest flagship handset, the company makes a brave attempt at a smoother sail in American waters, but a disappointing screen makes the Z1S founder. Sure, its 5-inch display is big and boasts a full-HD resolution, but it lacks the visual impact of Sony's high-end competitors like the Nexus 5, the S4, and the Galaxy Note 3. Heck, even older handsets such as the HTC One serve up more inviting eye candy.

Still, there is plenty right about the Z1S. Equipped with a speedy Snapdragon 800 processor, a full 32GB of internal storage, elegant glass construction, and a sharp 20MP camera, the Xperia Z1S is Sony's best carrier-branded smartphone yet. And available exclusively through T-Mobile, it's reasonably priced for the carrier's no-contract model ($528 up front or 24 monthly payments of $22). But even so, I wish that T-Mobile were selling the Xperia Z1 Compact instead. Astonishingly, the Compact matches the Z1S spec for spec and it boasts a higher-quality (if smaller) 4.3-inch display.

Design and build quality

If you have a soft spot for Sony's current Xperia lineup of mobile devices then you'll quickly warm up to the Z1S. It uses the same jet-black color scheme, sharp lines, glass panels, and silver accents gracing the Xperia Z, Xperia Z1, and Z1 Ultra. I admit I like the Xperia design language, which manages to be both sober yet sophisticated. It also helps Sony phones to stand out in a world overcrowded with look-alike plastic mobile gadgets.

The premium aesthetics of the Xperia Z1S do come at a price, however, namely glossy and highly reflective surfaces that attract finger grease and prints like it's going out of style. The Z1S' smooth sides also felt slippery in my hands, which caused me to yearn for the soft-touch frames of other phones.

Measuring a svelte 0.34-inch thick by 5.74 inches tall and 2.91 inches wide, the Xperia Z1S is quite pocket-friendly, though. Indeed, it's way more practical to grip and operate in one hand than Sony's behemoth Z1 Ultra. With the exception of a dedicated camera shutter key on the right edge, Sony keeps the phone's physical controls to a minimum too.

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A circular silver power button and thin volume rocker are the only other hardware keys. To keep them protected from the elements, the Xperia Z1S hides its microSD card slot, SIM card slot, and Micro-USB port behind stiff flaps. Up top is the 3.5mm headphone jack, while the device's bottom lip houses a trim but long stereo speaker.

Display

With a full-HD resolution of 1,920x1,080 pixels, the Xperia Z1S' big 5-inch display is bright and renders crisp text and images. The screen's colors looked vibrant as well, though its LCD technology can't match the eye-popping hues and high-contrast of Samsung's OLED handsets. And in the short time I spent with the device it was clear that viewing angles drop sharply when not viewing the screen head-on. Also, colors adopted a distracting milky sheen when I twisted the phone slightly left, right, or up and down. I even experienced the unsettling effect when the device was placed flat on nearby desktops -- within arm's reach from my chair, mind you.

Sadly, the reason for this visual shortcoming is that the phone's LCD screen lacks IPS (in-plane switching) technology. Because they have much higher contrast than traditional LCDs and don't wash out off-angle either, IPS displays have become standard in today's LCD-equipped smartphones. It's really a shame that Sony chose not to outfit the Z1S accordingly.

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Fearless of spills and grime

Thanks to Sony's dedication to giving the world water- and dust-resistant smartphones, all it takes to get the Xperia Z1S sparkly clean is a quick rinse. Just like the company's other Xperia gadgets, the Z1S is able to withstand submersion in water and exposure to rain as well as dirt particles.

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Sony says the Xperia Z1S is rated to meet the IP58 durability standard -- essentially that means in addition to shrugging off sand and grit the device can survive prolonged dunks (30 minutes) in up to 4.5 feet of water. I can confirm that my Z1S test unit was as hardy as advertised. It's also a great comfort knowing that wet sink countertops or the odd drink spill won't faze this gadget.

Camera prowess

Around back you'll find the handset's main 20.7-megapixel camera and LED flash. Sony also touts that the Xperia Z1S uses its more premium G Lens, which it claims is superior to ordinary camera phone glass (though I bet it's constructed from quartz or clear plastic). Indoors the Z1S handled itself well and pictures of still-life images were well exposed, with accurate colors and clear details.

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Outside photo quality was high as well, even when I shot under the weak winter sun and overcast skies of New York. I was able to capture images of wily, quick-footed children as well. The only real complaint I have is that the Z1S' camera takes its own sweet time to focus, which forced to me to fire many shots in a row for fear of missing the action. I also noticed that the camera's shot-to-shot speed was sluggish, at about a second between consecutive photos.