Hardware
We've teased a bit of the Pantech Flex's internals already, but now it's time to discover what it's all about. The smartphone wields a Qualcomm Snapdragon S4 SoC (MSM8960), which combines a 1.5GHz dual-core Krait CPU, an Adreno 225 GPU and a plethora of connectivity options. This includes LTE support across the 700, 850, 1700 / AWS and 1900MHz bands, alongside HSPA+ support for the 850, 1900 and 2100MHz bands. For times when you're out in the boonies, there's also quad-band GSM / EDGE access. Keep in mind, however, that you'll need to unlock the Flex to use networks outside of AT&T's reach, and even then, the phone would only be of much interest to T-Mobile's US subscribers in areas where the carrier has repurposed its 1900MHz network for 3G access. As you might expect, the phone also offers 802.11a/b/g/n and WiFi Direct, Bluetooth 4.0, along with both GPS and its Russian equivalent, GLONASS. Unfortunately, the Flex lacks NFC, which means no support for Android Beam or NFC-based payment systems such as Google Wallet or Isis.

While the Pantech Flex is no doubt a budget smartphone, its 4.3-inch qHD (960 x 540) display is among the best in its category. It offers excellent touch response, fantastic viewing angles and higher-than-average resolution. That said, even though the individual pixels are packed a bit more tightly than WVGA (800 x 480) alternatives, the Super AMOLED display features a PenTile matrix, which causes text to appear slightly blurry. Naturally, advantages of Super AMOLED displays include deep blacks, increased color saturation and better vibrancy. Unfortunately, the screen is less than ideal for use in direct sunlight. It's also worth mentioning that if you're not an AMOLED fan, the LG Escape for AT&T ($50) offers a similar 4.3-inch qHD display, albeit with an IPS screen for better sharpness.
The Pantech Flex arrives at AT&T as a natural successor to the Burst. While its older sibling succeeded in its effort to bring dual-core processing and LTE speeds to the masses, its thick, plasticky enclosure made it difficult to ignore its budget status. In that regard, it's easy to understand what Pantech hoped to accomplish this time around. With the Flex, Pantech has eschewed the all-plastic enclosure in favor of a more industrial design that sports a hybrid of plastic and metallic finishes. It's also larger and slimmer than before, measuring 5.1 x 2.6 x 0.32 inches (130 x 66 x 8mm).

The Flex's design is best described as haphazard -- imagine if the Samsung Focus and Droid Incredible 2 had met in one regrettable late-night tryst. Above all, its design is manic and lacks cohesion; almost a split personality that's symbolic of the two software environments. Both the volume rocker and power button sport textured finishes that make it easier to locate the controls by feel. Unfortunately, this smart move is completely negated by the poor location of the power button: it's positioned in the middle on the right side. Right-handed folks will discover that their thumb naturally covers the exposed microUSB port, which is exactly where the power button should be. Instead, not only does this make it more difficult to wake the device or put it to sleep, but it also means that the microUSB port will eventually collect gunk from your fingers, which could lead to hardware issues. This isn't so much of an problem for left-handed folk, but the majority of people will likely loathe the layout. There's also no notification light, which is unfortunate, but a relatively minor sacrifice.
One of our primary complaints with the Pantech Burst was its set of unresponsive capacitive buttons. That's a non-issue this time around, as the navigation keys of the Flex are completely software-based -- just like the Galaxy Nexus. The end result is a cleaner look up front, in addition to the elimination of wasted space. For every battle that the Flex wins, however, the smartphone loses another. In this case, it's the raised edge of the frame that surrounds the display. Needless to say, it causes an unsettling feeling every time your thumb crosses the harsh edge, and your only hope is that you'll eventually wear down the plastic to make it flush with the display -- by that time, however, you'll probably be looking at a new smartphone.

Removal of the Flex's rear cover is relatively painless, which is a good thing, considering that the phone will be sold in part to the elderly. Underneath, you'll find a substantial 1,830mAh battery, in addition to slots for the micro-SIM and microSD cards. The phone includes 1GB of RAM, along with 8GB of built-in storage with approximately 5.5GB available for use. Eco-minded shoppers should know that the Flex ranks relatively low on AT&T's sustainability scale, with only two out of a possible five stars. For a more complete overview of the Pantech Flex, we've included a spec sheet for quick reference.
Performance and battery life

With a Qualcomm Snapdragon S4 running the show, it should come as no surprise that the Pantech Flex can run with the big dogs. The phone offers a dual-core 1.5GHz Krait CPU, and it's immediately apparent that the Flex offers the same level of performance and responsiveness that keeps One X and Galaxy S III owners grinning. Outside of the poky camera app, mainstay titles such as Chrome, Gmail, Maps and YouTube all pop open without hesitation, and switching between apps is a similarly breezy affair. Within the browser, web pages render quickly, and actions like panning, scrolling and zooming are all buttery smooth. The same can be said for animations and transitions within Pantech's launcher, which is wonderfully responsive. From a cold boot, the Flex delivers you to the lock screen and then straight into the launcher in just under 30 seconds. Benchmarks reinforce our real-world impressions, which suggest the Flex performs roughly in line with the One X for AT&T. Call quality is a similar strong point, which was consistently clear and free of distortion.
Aboard AT&T's LTE network in Portland, Ore., the Flex averaged 10.7 Mbps down and 6.3 Mbps up. That's more than sufficient for most needs, but it's roughly one-third of the chart-topping speeds we've seen for the carrier. Even with LTE enabled, we averaged between 36 and 42 hours of battery life with moderate use. Meanwhile, in our standard battery rundown test, the Flex was able to squeeze out eight hours and 34 minutes of uptime before calling it a day, which is on the better side of average and just short of the One X.
Camera

As an upgrade over the Burst, the Flex now features an 8-megapixel rear camera that's paired with a 2MP front-facing shooter. Even with the new setup, however, Pantech's implementation continues to disappoint. To its credit, the camera now captures a greater amount of detail than before, and under a narrow set of conditions, it delivers very nice photos. That said, you'll consistently find overblown highlights that are impossible to eliminate within the EV settings, an issue that holds true even in ideal lighting. The camera performs poorly in the shade, where highlights are overexposed, shadows are underexposed and colors appear washed out and muted. Fiddling with the white balance can sometimes prove helpful, but even then, colors are far from accurate. Meanwhile, 1080p video capture is smooth and fluid, but the camcorder suffers from the very same weaknesses as the still camera. In an ironic twist, the Flex performs quite well at nighttime in HDR mode, but that small victory isn't enough to salvage an otherwise forgettable camera.