I cruise fairly frequently (2-3 times a year).  Carnival Cruise lines draws a younger, rowdier crowd than most of the other cruise lines.  This is has advantages and disadvantages.  The pluses are that we are younger (early 30's) so there are always more people our age on Carnival cruises.  The cons are that we really enjoy elegant cruises, and Carnival is more casual.--and with a lot more kids/teens.  You very well might hear yelling/laughing/running up and down the halls at 3 and 4 in the morning.

The Miracle is one of the newer, larger ships.  We enjoyed the ship and the various rooms...