This very long thread already has many pricing comparisons, but I thought I would share another one since I'm shopping and have the pricing.
I priced out an Eastern Caribbean leaving in late August from Port Canaveral for three lines. Carnival Breeze,
Royal Caribbean Harmony of the Seas and Disney Fantasy. They all go to slightly different ports and have vastly different pricing. We've been on the Breeze and Fantasy before so know what to expect. We've sailed on Royal, but not Oasis class. But we feel we have a pretty decent idea having been on the Freedom.
Carnival Breeze:
August 24 7 day Eastern Caribbean
Grand Turk, San Juan, St. Thomas, Amber Cove, day at sea
Deck 7 Aft Balcony is $2,169.94 (incl taxes and port fees)
Harmony of the Seas:
August 25 7 day Eastern Caribbean
Perfect Day at Coco Cay, St. Thomas, St. Marten, 2 days at sea
Deck 9 Aft Balcony is $2,442.66 (incl taxes and port fees)
Disney Fantasy:
August 24 7 day Eastern Caribbean
Tortola, St. Thomas,
Castaway Cay, 2 days at sea
Deck 9 Aft Balcony is $4,607.04 (incl taxes and port fees)
The pricing is about as comparable as you can get between lines, although we all know that on the Fantasy you get a larger stateroom with a split bath and the other "Disney" difference. Does that justify double the price? Not in my mind. Not even close. I'm willing to pay a premium for Disney, but not that kind of premium.
Frankly the Royal Caribbean option looks to be the best value to me. Only slightly more than the Breeze and we get to experience the new private island renovations and we love the extra sea day. We haven't tried an Oasis class ship, so this would be a new experience whereas both the Breeze and the Fantasy are familiar. However, we really enjoyed our cruise on the Breeze so it also very appealing.