We priced out a B2B for February versus an Eastern on Fantasy (SWDAS). We had already done the SWDAS, but enjoyed it and would have repeated it for the right price. The cost difference ended up over $1300 cheaper to do the B2B with two stops at Castaway.
Posting this with the caveat that it really depends on the time of year you are looking at, as I am fairly certain that SWDAS is what kicked the price so much higher for the Fantasy that week.