One big difference in Carnival and NCL is the dining. If you eat in the main dining room you will be asked if you want to sit with anyone else and there is a very good chanced that you will end up by yourselves. Also NCL has many more place to eat but you have to make a reservation for all but the main dining room and buffet and more than one will have extra charge.
We really like meetingand eating with others while on a cruise so NCL definetly was not for us, even when we did the Your Time Dining on Carnival when we said we would sit with others we did sit with other but not so on NCL.
Star Princess 2005, Sun Princess 2005
Caribbean Princess 2006, MSC Lirica 2006 , NCL Pearl 2007, Majesty of the Seas 2008, Carnival Destiny 2008, MSC Lirica 2009, Carnival Valor 2009,Carnival Legend 2010, Carnival Liberty 2010,Carnival Fantsay 2011,Carnival Valor Feb 2012, MSC Poesia Dec 2012, MSC Poesia April 2013, Carnival Legend Nov 2013, MSC DIVINA Jan 2014