http://www.androidcentral.com/galaxy-note-4-launch-ahead-schedule-samsung-ambitious-sales-targets
Granted, probably not on Sprint (or anyone in the US) considering Sprint's preorders are a week later than others.
Samsung didn't do this well. Sure, you announce ahead of the iPhone, but then don't even give a release date until after the launch? Don't assume that possible Note 4 buyers won't look at the iPhone. I probably won't, but the RF performance of the iPhone 6 is sure temping.
If the 6+ wasn't even BIGGER than the N4 that would make it more convincing...