My wife and I took the Cunard Queen Mary 2 World Voyage 2010 - Our trip started in Southampton January 11th and we left the Queen 91 days and 33 ports later in Ft. Lauderdale.
The size of the Queen affords the passengers the luxury of large public rooms and lots of space to lounge around. The airiness and many large windows gives the light and view a chance to be admired by all passengers from every direction. The down size to this large vessel, is that you see all the major container ports of the world; the ship is so large (155 thousand tons) that it does not accommodate the ports well, and one docks miles from the center of passenger interest. The shuttle service takes anywhere from 45 minutes to one hour to transport the passengers to town and the lines are long; and in some ports, no cover was available to shade the passengers from the heat, and a few passengers fainted while waiting to board the ship..The lack of water at the port stations were very obvious to all. If the ship is your "destination", this ship has what you want. If you are concerned about seeing the ports in detail, and with maximum time, you will need to go on a "cruise" ship, not an ocean liner; the QM2 is a great venue for quiet elegance an the enjoyment of serenity, but you can also be busy all day long if you choose.
The food quality ranges from 5 star cafeteria to excellent; the quality was not consistent from day to day. The Kings Court venue with its four no charge alternate dining restaurants are a nice touch from the main dining room. The service in the Kings Court was always above par. The food was excellent; but you were limited to two reservation per cruise segment, and when making the reservations, one had to call many days in advance as the space is extremely limited.