I got up around 4:30 (central) on my ADR day, and was able to start booking my ADRs. I was so successful that I went back to bed around 5:30, and didn't even bother staying up until 6am to call.
The only thing that didn't work for me was booking Hoop dee doo. I still can't get it to recognize that I'm on the Dining Plan, so it wants me to pay in full. At some point I'm going to call about this, but I'm not too worried.