One "substantiated" disadvantage - the large catamaran on the T-slip at the end of our marina dock, is scorned by everyone who tries to navigate around it - including us. It takes up the space of two mono-hulls. I would also imagine the relatively wide beam to be a negative in tight-quarters maneuvering
We sailed on a 42 footer last year in Key Largo and while scuba diving off the outer reef while at anchor in 2-3 foot seas, the boat had an awkward pounding and slapping motion. However, the amount of space was very luxurious.
True Blue . . .
sold the Nauticat