We've dined at both a number of times...well at Narcoosse's many times including the old days when they served lunch....but anyway we enjoy both but they are different.
Narcoosse's specializes in seafood. It has a beautiful view of the lake and the lights of the MK, CR and Polynesian. It also has wooden floors so can be a little loud some nights depending on the crowd.
Citricos is a very large restaurant that is usually not close to being filled although it certainly was full last Christmas Eve. The views are of the courtyard and buildings of the GF other than a few tables at the end of the restaurant. Those tables can see the FW at MK although not the castle as I recall. The overall feel is more elegant I think.
The food at both is excellent and the service usually is, too.
I would check the menus and see which appeals to you.