Dan,
Everyone's preferences and priorities are different. My complaints about the Constellation are in 3 areas--the ship, dining food and service, ship activities. Compared to previous Celebrity cruises this ship didn't have the areas I enjoyed on the earlier ships, the dining food's presentation and quality was not up to the level of the previous cruises, and the ship activities were not as extensive, by this I mean more of the staff involvement with activities and the length of time that musicians performed. I love hearing jazz on Celebrity and I didn't hear much on this cruise. For some these things do not matter.
A near perfect cruise is hard to predict. On any line you need to get at least competent, if not outstanding, cabin stewards, dinner waiter and assistant team and a fine wine sommelier and Maitre 'd enhances this, as well as some standouts in other areas without noticing any shortcomings in service. Sometimes you need great weather and not to miss any ports. Sometimes, actually usually, you need compatable table mates. Sometimes it is the entertainment whether it is musicians playing or showroom entertainment. I got this near-perfect cruise on Celebrity's Galaxy in Alaska in 1999. I think the world of that ship, I much prefer her to the newest crop of Celebrity's ships. To be honest with you I'm not a newer is better type of person. I like unique ships, so I don't like carbon copy series of ships, and the Century class Celebrity ships are not carbon copies, the Millennium ships are. Some of the ships I like besides the Celebrity ships are the P&O Oriana and Aurora, Cunard's Caronia and QE2, and there are some others. I think RCI's Voyager class is big and busy for my tastes but is a well designed product that really works for RCI style of cruising. I think that the Celebrity Millie ships don't work as well for Celebrity because they weren't totally designed by Celebrity. All I can say about them is that they don't divide and put on different levels intimate sections in big public rooms, don't have enough dance floors, and waste space in too many areas. They are pretty and posh, that's not enough for me.
To answer your question I would need to know what you prefer. But it could be any line. If you like freestyle or optional dining NCL and Princess are good choices. However, it is up to them at the time of your cruise to deliver the product, and nobody knows what a given product will be like a given week or the makeup of the passengers that can impact a cruise. So, I would go with whatever seems to fit best and then hope to get all of the factors to go along for what you consider a wonderful cruise.
