I'm going to hold off for a while, but just so that everyone is aware, the AT&T version apparently ships with a locked bootloader, which means any rooting of that version won't happen until (and if) the hacking community figures out how to unlock it.
They have already have a unlock if i have read correctly.
If you have a link, please let me know. The one article that showed how to root the S4 wasn't done on the AT&T version, I don't think. This is what I saw:
https://plus.google.com/u/0/100275307499530023476/posts/b4AqTzzVKVS
I would like to hold out for the 32GB on AT&T, but the devil in me wants to use my upgrade as soon as it's available tomorrow.