Makaroni, depending on who you booked with, and how far out you are, you can still switch your booking over. If you have made your final payment, you definitely can't switch over.
We booked our May cruise last year with AAA, and our Jan cruise this year direct with Disney. Last May, AAA was offering mugs, $100 stateroom credit, and 10% discount on ship stores and
Castaway Cay merch. This Jan, they weren't offering stateroom credit.
At least our AAA didn't have anyone knowledgeable about
DCL, so they weren't any help. However, they forced us to come in to the office (for us, that's over 2 hours one way from our house) to pick up the cruise documents "so they can go over them with us to answer any questions we had". Kind of a minor thing, but when we were booked with AAA, we couldn't pull up our reservation on the DCL site. Booked directly w/ DCL (and as far as I understand, with Dreams), we could go to the DCL site and see our reservation directly, and email any shore excursions, etc that we wanted. I also got to see our free upgrade (from a cat 9 to a cat 5) right when it happened (woo hoo!).
For our Jan trip, we were only going on a 4 day (May was 7), so the mugs were cheaper. We also noticed that we really only used two of the mugs, because the kids spent most of their time in the clubs (where they can't go out for sodas). We ended up just booking directly w/ DCL and buying 2 mugs when we got on board.
I wouldn't book w/ AAA again unless they offered more of a credit than any other reputable agency. I'd probably start with
Dreams Unlimited.