I was up at 12:01am to order my X but like many, I also got the error message several times and eventually received the message that a phone would be reserved for me to complete the check out later. Not knowing if this would save a place for me in line or not, I kept trying until I finally got though with a delivery date of the 17th to the 24th. While I would have liked to get it on the 3rd (who wouldn't), it wasn't a big deal and went back to sleep.
When I woke up a few hours later, I received two emails with my reservation number to complete my order. So out of curiosity, I went though the steps but because I had eventually placed an order several hours ago, the system would not let me place another order. I also was not able to see what the expected delivery would be with my "reserved" phone. Well, because I wasn't in a hurry to get the new phone, I decided to gamble and cancel my order from my first attempt and reorder using the reservation number in the email. I just waited a few minutes after canceling and the system let me place my order with a delivery date of the 3rd. Awesome!
I did get that "reserved" message fairly early during my original attempt this morning (about 12:07am Pacific) which is why I figured there was a good chance I would at least maintain my allocation or potentially improve it a bit, which is what happened. So if anyone got their "reserved" message early in the order attempt process, you might want to try it but no guarantees of course!