I downloaded it with KIES last week and have had no issues at all. In fact, I'm thrilled with it! All around it seem more responsive and I know for a fact my battery life is better. As for the process, its pretty simple. Just find the KIES program for your computer on the Samsung website. Connect your phone to the computer and run the program. It will walk you thru the rest. Most of the time is just spent waiting for 4.3 to download. 4.3 is a big download so it might take a while unless you have a very fast connection. It really is very simple to do.