The drink package is usually free, for us it is a no brainer to get. you can get more than one...... Hell, last year on Meraviglia I got a 12 pack of Miller Lite brought up on deck so I could smoke cigars.
Carnival appeals to the masses. Sailed them a few times, but nothing special. I feel the food on MSC is better. The pizza definitely is. Carnival is ok, just not for me.
Just saw your definition here. I have never sailed on those other 4 lines. I like the Yacht Club, and am fine with cruising soley on there. The other 4 you mentioned seem to have typically smaller ships.
Carnival is bleeding cash, old outdated ships.
NCL is cutting back but still an awesome cruise line
RCCL is interested in making Mega Ships.
MSC can do what they want, they have the deepest pockets.
Competition is always good for the consumer.