It depends on your tastes- Chops is a very fine steak house restaurant - steak, pork, lobster, lamb etc..
Portifinos is an Italian cuisine fine dinning.
Personally, if I am going to pay extra on a cruise ship its going to be for a great steak, but you can decide for yourself.
Weather in October should be good. You chances of running into a storm have lessened by then. (Though its still possible)
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007