If you have only done Carnival, I suggest trying something else. IF the only ice cream you've ever had was vanilla, then vanilla is the best ice cream. I've done 4 Celebrity, one Carnival, one RCCL and one NCL. Celebrity was best, NCL worst, Carnival, sort of meh.
Breeze. It's the newest ship. Sunshine is way smaller and older although it is fully renovated. I would still without a doubt choose Breeze though