I did get quotes from Dreams, but unfortunately they couldn't match the rate I was able to get from mousesavers web site. It was something to do with special offer dates. As long as I booked our first night on or before the last night of the special offer, the offer rate applied for the whole of our stay (in our case through the peak time President's weekend.) Dreams could only book at the offer price up to the last day, and then the price reverted to standard room rate after. I've no idea why there was this discrepency, I was disappointed as Dreams were so helpful and I felt a traitor not booking through them!!
Perhaps they can only book through the WDW Travel Company and not Central Reservations Office, I don't know. CRO give better cancellation terms etc, so try and book through them if you can.
Hopefully, you can get a good rate through Dreams, and once they have your reservation they do all the leg work for you, booking PSs etc (even Cinderella's Royal Table apparantly!!)