All the talk about Android L this week overshadows the unfortunate fact that the previous release is still on less than 15% of Android devices. This weekend US Cellular is helping in a small way, releasing KitKat to two of its Samsung phones. The US Cellular versions of the Galaxy S4 Mini and the Galaxy Mega (6.3) are both being updated to KitKat, so those with the applicable hardware should keep an eye out for the over-the-air alert.
Unfortunately this is KitKat 4.4.2, not the more recent 4.4.3 or 4.4.4, but most users won't be able to spot the difference. According to US Cellular's support page, the updates are available over the air or via Samsung's Kies desktop program for impatient users. That might be a better option anyway, if you want a faster download that won't eat into your data meter and you don't have a solid WiFi network handy.
US Cellular's documentation is pretty sparse, but you can expect all the goodies from the AOSP version of KitKat, plus a few touches from newer Samsung versions of TochWiz (or whatever they're calling it this quarter). As always, If you've rooted or otherwise modified your phone the standard OTA update will probably fail, so you'll have to find another way of getting onto the latest software release.
Source: US Cellular Support