There's a Canada thread already that might have a lot of feedback/responses already...
But I was in the same boat (along with several others I spoke to). By the time the site was up and the app was working smoothly (~5:30), it seemed like most iPhone 6's were still possibly for 9/19 but most if not all 6 Pluses showed 3-4 weeks.
I was on the app on multiple devices trying over and over. Around 4:30 I did get a few orders in, one of them a 6 and the other a 6 Plus, both for 9/19.
Frustrating overall though.