I would be very surprised if the apparent 128GB version is offered in the US.
Not seeing the value in 6GB for Android, based on the cache method for apps. Diminished returns at 3GB and then more so at 4GB. At least that is the case now, but as apps/games get a lot bigger on average, this could maybe possibly be an issue, but that is down the road where the Note 7 would be a relic (battery would be dead by then).
The main bottleneck with Android is the cache method and the code translation layer combined with that. Cashe access to address locations is essentially in series and relies on clock cycles to compensate, but still in series and at the mercy of the regression algorithm used for historic app access. To mitigate lag events, there needs to be multiple parallel streams with a very savvy CPU/RAM controller working with cache management. Fancier chips means more money to design / fabricate and a rethink on current SOC design.
Folks dwelling on 6GB are respectfully worried about the wrong thing. 4GB is more than fine.