Last week, AT&T had begun pushing the Android 4.3 update to the Galaxy S4, but they had to quickly pull it for some untold reasons. Some people were able to download the update while others were unable too. The build number was 1337UCUEMJ9 and now they are pushing out the update again, this one's updated a bit and is now build 1337UCUEMK2. AT&T doesn't tell us what the different between the two is, but it doesn't really matter these days.
The update is pretty hefty, but then again, most Touchwiz updates are pretty hefty. This one is about 727MB in size. Otherwise, the update is just as you expected, and we even have the changelog available for you:
Android 4.3 OS upgrade (www.android.com/whatsnew)
Samsung Galaxy Gear compatibility
Drag and drop to uninstall or disable applications
Call reliability improvements
For most users, they won't notice much of a change with this update, as Android 4.3 is mostly all under-the-hood changes. The biggest improvements you'll see is the ability to drag-and-drop applications to uninstall or disable them. As well as call reliability improvements. Which is probably exclusive to the AT&T Galaxy S4. Oh and there's the Galaxy Gear support too. But there's supposed to be another Galaxy Gear coming in the beginning of 2014 anyways, so I'm not sure that's a huge deal.
The update is available now and is pushing out to everyone. You can try and pull the update by going into Settings > About Phone > Software Update > Check for Update. Remember that AT&T only allows you to check for updates once every 24 hours. So be careful.
How many of you had gotten the original update? How did that update work for you? Whatever the issue is, it looked like Samsung and AT&T got it fixed rather quickly, since it's pushing out now. Let us know how the update goes for you in the comments below.