I already preordered through the Apple Store app, but if it's anything like what happened when I tried to preorder the 5 through Apple, they'll cancel my order because I'm on a family plan and tell me I have to go through Sprint, leaving me in the dust.
Soooooo, I went ahead and preordered through the Sprint site as well. This was my original plan except for the fact that it was DOWN FOR THE FIRST FOUR HOURS so I had no choice but go through Apple. All good though, because it worked flawlessly at 7 AM EST, got the model I wanted (64gb 6 in space gray), AND it arrives on 9/19.
So I actually have two preorders for one line, but once I get my shipping confirmation from Sprint, I'll go ahead and cancel my Apple reservation, which is probably going to get canceled by them regardless.
Moral of the story: sleep in next time, and just go through Sprint.