Galaxy SIII SCH-I535, Android 4.4.2 - High Battery Drain
When I first received my SCH-I535, it performed an OTA update. I was shocked at how much battery this brand new Samsung was using. After lots of research, I reinstalled the update through my PC. You need to attach with a USB cable, let it install software from the phone onto the PC and perform a phone system update through the installed software. Basically, something got messed up with the OTA update. Reinstalling the update through the PC fixed the battery drain.

Also be aware, though, that if you're coming from a phone that didn't have an AMOLED, like an HTC, you're used to seeing the display hogging all the battery. On a Samsung, you're more likely to see the OS using more power than the display.

Hope this helps!