Although it's backordered right now and I have to wait another week for it to arrive, ( SUCKS because I even got FedEx 2 Day Shipping! ): )
I can POSITIVELY and SURELY CONFIRM that:
C6833 Works on all networks INCLUDING 4G LTE for T-Mobile as this uses BAND 4
C6806 Works on all networks INCLUDING 4G LTE for T-Mobile and AT&T
C6802 Works on all networks EXCLUDING 4G LTE
Hope this clears up any confusion. The International version of the Xperia ZU will work on all networks that have 4G LTE as well EXCEPT AT&T'S, presumably because it does not have the supported band. (I cannot confirm but am 99% sure) The North American (US) version will be slightly cheaper by $20-$50 depending where you order it from. The only true benefit of this (besides saving money of course) is the ability to connect to AT&T's 4G LTE network. Other than that, they are both the same. (EXLCUDING C6802 which does NOT support ANY 4G LTE speeds)
If you don't want to wait until after October 14 like me, go ahead and get the international version. Some websites have good deals and you might be able to get it at an equal price OR cheaper compared to the C6806 if you look wisely and do your research.
Personally, the international version is the way to go if you aren't on AT&T's network because if you ever go somewhere outside of the US, you can still use prepaid phone plans or such and access the internet. For such an amazing device coming with a premium price tag, I'd like to be TRULY mobile with my phone!
PLEASE stay tuned as when my Xperia ZU arrives I'll do a live video of me taking off the Anti-Shatter Film as some of you wish to do so. (Same here) I'll also post up some pictures of the cases I have and screen protectors I'll be using (SPIGEN TEMPERED GLASS COMING SEPT. 30!) and various tests (NOT the usual ones you see of benchmarks and such, but rather more interesting ones like size and everyday practical use)
If you guys have any questions just feel free to ask, we're a community here so let's see what valuable knowledge we can offer!