We just love HTC's One X here at Engadget -- it's quite possibly our favorite smartphone of 2012. Three devices have crossed our desks over the past year -- the original with HSPA+, AT&T's model with LTE and, more recently, the global One X+ with HSPA+.
Put AT&T's One X+ face-up alongside its international cousin, and you'll notice the carrier's familiar globe replacing HTC's logo on the glass just below the earpiece and the capacitive buttons, which are now white instead of red. Flip the phones over and the global One X+'s red accents give way to a completely black design -- the red circle around the camera lens is gone and the Beats logo is now gray.
What's more subtle is how the docking contacts on the back of AT&T's handset are offset a few millimeters from its foreign sibling, just like we saw on the One X. Compared to the original, which is available in white or gray, you can have the One X+ in any color, as long as it's black.
While the One X packed either NVIDIA's quad-core Tegra 3 with 32GB of storage or Qualcomm's dual-core Snapdragon S4 (for LTE support) with only 16GB of built-in flash, the One X+ features a faster Tegra 3 AP37 (1.7GHz vs. 1.5GHz) with a whopping 64GB of storage across the board.
There's still no microSD card slot, but the 1GB LPDDR2 RAM carries over from the One X along with the gorgeous 4.7-inch, 1,280-by-720-pixel Super LCD 2 display (now covered in Gorilla Glass 2) and the excellent 8-megapixel autofocus camera (with BSI sensor, 28mm f/2.0 lens, ImageChip and LED flash).
The front-facing shooter gets updated (1.6MP BSI vs. 1.3MP) and the sealed battery grows from 1,800mAh to 2,100mAh. Clearly, the One X+ is an improvement over the original, but this time around AT&T's model is almost identical to the international version. The only major difference is in the radio chipset. Unlike the global One X+, which features Intel's X-Gold XMM6260 for quad-band DC-HSPA+ (850 / 900 / 1900 / 2100MHz) support, AT&T's variant uses Qualcomm's MDM9215 for dual-band LTE (700 / 1700MHz) and tri-band HSPA+ (850 / 1900 / 2100MHz) access.
Of course, both devices also provide quad-band GSM / EDGE connectivity, 802.11a/b/g/n, Bluetooth 4.0, GPS / GLONASS and NFC. As documented in the benchmarks below, there's very little difference in terms of performance between AT&T's One X+ and its international sibling. The carrier's model scores slightly lower in most tests, but both phones feel snappy enough.
We noticed a little sluggishness during initial setup when navigating the UI while updating a dozen apps, but it's been smooth sailing ever since. In our usual battery rundown test (endlessly looping a video with the brightness set to half, and with push email and social networks polling enabled) AT&T's One X+ ran for seven hours and 23 minutes -- just shy of what we measured on the global version. LTE networks speeds in San Francisco averaged about 12 Mbps down and 8 Mbps up with peaks of 20 Mbps down and 14 Mbps up -- no surprises here.
If you're in the US, should you pick AT&T's One X+ over the foreign model? Yes, definitely. Despite suffering slightly from carrier bloat, it features LTE and costs significantly less, even unsubsidized ($550 vs. £474 / $764). More importantly, should you get AT&T's original One X instead of the newer version? While the older phone sells for as little as $0.01 with a two-year agreement and typically retails for $100 on the carrier's website, the One X+ costs $200 on contract.
If storage is critical, there's no doubt that AT&T's One X+ is the smarter choice; 64GB vs. 16GB is nothing to sneer at. Otherwise, we think the One X offers much better value. Ultimately, these handsets are among HTC's finest, so you can't go wrong either way, and if you don't care about style, there's always AT&T's Galaxy S III ($200).