The OnePlus X is an interesting device. OnePlus have taken many of the components of the original OnePlus smartphone, the One, and repackaged them into a less expensive model than their flagship OnePlus Two. The result is an inexpensive, well designed smartphone based around the Qualcomm Snapdragon 801 System-on-Chip, which was used in many 2014 flagship devices. The 801 is backed up by 3 GB of RAM with 16 GB of internal storage plus a MicroSD card slot. There's a 5.0-inch, 1080p resolution, AMOLED panel, a 2,525 mAh rechargeable battery and support for LTE. The device is very much a mid-range model, but rather than using a newer generation mid-range chipset, it uses a former flagship chipset. This decision is almost certainly on the grounds of cost and we could speculate as to how much cheaper Qualcomm has made the Snapdragon 801 compared with the Snapdragon 617, for example, but in terms of processor and graphical power, the 801 is more than capable of running today's Android software well.
However, one area where using an older chipset can have an impact is the frequencies that the LTE radio supports. To be more precise, the LTE bands that the OnePlus X supports does include the US carriers but excludes the newer 700 MHz spectrum bands - Band 12 and Band 17 - which the carriers use to provide solid LTE coverage inside buildings or over long distances in rural environments. The reason why these bands are liked by the carriers is because the lower the frequency, the longer the range of the radio signal and the better it penetrates buildings. This means a better, more reliable LTE experience for customers, which makes people happier. It also means that the network does not need to build so many masts to provide effective coverage and it will eventually reduce the data load on the 3G network. The OnePlus X supports Band 1 (2,100 MHz), Band 2 (1,900 MHz), Band 4 (1,700 MHz), Band 5 (850 MHz), Band 7 (2,600 MHz) and Band 8 (900 MHz). As such, it is atypical of older LTE smartphones but it does mean that the device may drop to a 3G or - the horror! - a GPRS or EDGE connection in some parts of the world. OnePlus have confirmed that they have no plans to change the design to incorporate the new LTE frequencies.
How much does this matter on a $250 device, especially when alternatives offering the newer bands are available for about the same (such as the third generation Motorola Moto G)? That depends. For a customer moving from an older device with support for Bands 12 and 17, he or she may notice that their new OnePlus X does not offer as robust a connection. For customers moving from a smartphone with no LTE support, yes perhaps they are not getting the best possible LTE experience from their carrier, but many people looking at a mid-range device either do not care for, or accept, any compromises along the way. The line of thinking that the OnePlus X is a terrible device for lacking these LTE Band support is missing the point.