Welcome to the KitKat club, US Cellular
If your Moto X is U.S. Cellular branded, you'll want to check for an update to the OS. Motorola's Punit Soni has announced that the KitKat update for USC models of the Moto X is currently rolling out in stages,
When finished, don't expect things to look very different. Under the hood though, well that's another story. Changes to resource management will keep your Moto X running snappy even while more apps are open and running, and as new applications are written that take advantage of 4.4 features, you'll be ready for them.
Anyone on USC seeing this yet? Shout out in the comments!
Source: +Punit Soni