Kouzzina was definitely on the dining plan in September. We chose it over Flying Fish, and it was our second-favorite meal of the trip (after Jiko). We're trying Flying Fish this time. Flying Fish generally gets good reviews while Kouzzina's are more mixed, but like I said, Kouzzina was great for us.
I'd say that if Greek is one of your favorite types of food, do Kouzzina. Otherwise, do Flying Fish.