I'm in the opposite position as you. We had booked a cruise on the Dream for next summer and found out we are now on the Sunshine.
We have sailed on the Dream before and were going to do it again. I like the ship. The kids loved the waterworks. DH and I loved the spa. I think you will have a great cruise on Dream.
Carnival Celebration (Key West, Nassau)- June '07-First time cruiser
Rhapsody of the Seas (Alaska) - June '08
Carnival Freedom (Belize, Panama, Costa Rica) - June '09
Carnival Dream (Cozumel, Roatan, Belize, Costa Maya) - June '11
Carnival Freedom (Key West, Grand Cayman, Jamaica) Dec. '12
Carnival Sunshine (Nassau, St. Thomas, San Juan, Grand Turk) - June '14