So I had a nice, frustrating experience this past Saturday. I ordered at about 12:26pm Pacific Time this past Friday, which sounds like about 1.5 hours after the InStock notification went out (I'm not signed up; I had an order in with Apple and was just searching for news on if people were getting theirs from Apple earlier than the listed ship date of March 20). The customer service rep I chatted with at the time of my order insisted they were actually in stock (screencapped her guarantee). So I placed my order, then canceled the one I had with Apple.
Didn't see movement on it all day. Called them once I got home on Friday evening, and they couldn't tell me anything at that point. So I waited til Saturday morning and called them, and they indicated they couldn't see anything until at least 24 hours had passed from time of order, which was about 1.5 hours after I had called. Checked, no update (still "Processing Order"), so I opened up a chat again. That customer service rep "guaranteed" they would ship out for me on Monday (today), and the reason I hadn't seen an update yet was because it was the weekend. So it seems to kind of line up with what others in this thread are reporting, that whatever the CS reps are seeing on their end is indicating that there's actual stock they have (the rep indicated to me the order button would have been grayed out if it weren't in stock). So I'm keeping my fingers crossed. Once I hit the point today when my order was placed on Friday, I'll check again, and if I don't see anything, I'll give them til I get home this afternoon, and if I still don't see a change in my order status, it's back on the phone again until I get an answer from *someone*.
I'm cautiously optimistic right now.