I've used Orbitz MANY times in the past for those who are concerned.
I also wanted to update on my experience with Disney thus far. I booked on Orbitz last week. The next day, I got my Disney number from orbitz (chatted wiht CS) and then called Disney to add the reservation and cancel my Disney reservation. It as added to the
MDE site. My 60 day mark was 2 days ago and I did online checking. At that time, I changed the address because when you book through Orbitz, the reservation ends up with Orbitz' address (it's always like this, regardless of the hotel). I put in two requests - lake view and highest floor available.
Let's see... I still need to call and add my celebrations. I couldn't do that when Disney "adopted" the reservation. I also have to call and get celebrations added to my dining reservations since I made those online so I have to do both at the same time... So far it has been very easy.