Slow JB and Kies Solution
I got my S3 about a week ago and I love it! I've had a couple of issues with my device though but I did find solutions for it.
Kies won't connect to my device: I've tried everything to fix KIES, uninstalling, re-installing, troubleshoot, kies mini, and to no avail. Not once have i seen a post for an alternative to kies. I have and still have a problem with Kies. However, after doing a little bit of research I found an ALTERNATIVE program to backup your data to your computer. It's called MobileGO for android, download it on your phone and your computer, follow the steps and you will be able to simply backup your device! It's smooth and has an easy to understand user interface.
My Jellybean update runs slow: Backup your device with MobileGO, then do a factory restore to get rid of the old junk from the previous update. Restore your phone in MobileGO(the apps settings will be changed however). However, even by doing this, i noticed my Jellybean still was acting a bit choppy. Solution? Do you have the App "Light flow Lite?" installed on your phone? If so, try to disable it in the accessibility options. That works for me. JB works nice and smooth for me, no lag at all now!
Hopefully this saves some people time searching the web endlessly to find solutions to these problems.