I have booked myself and a friend on the Carnival Triumph in Dec 8, 2012. I have to say that while the Triumph is an older ship, I love the fact that the cabins are so large, it is kept so clean, well maintained and the staff so happy to take care of you; lots of activities.
I'm also now looking strongly at booking the Carnival Magic as prices have gone down and I like the port stops (Roatan, Belize, Caymans, Cozumel). I just looked last night and it's gone down to $544 pp for 7 nights. I'm hoping that by the time I book this one, the Magic will have worked out some of her "kinks."