Sorry - I was waiting for a response and googled to see if anyone else asked the same question and I found a lot of threads/articles on other sites where users said they upgraded with no problems. I went ahead and ran the JB upgrade through Kies and didn't have any issues *knock on wood*
It was fun having CM10 with JellyBean to tide me over, but the instability and constantly having to pull my battery out to reboot the phone was getting annoying. It seemed like the longer I ran CM10, the worse my phone got. Hoping that going back to AT&T's stock ROM of JellyBean will fix that.