Actually, longer and heavier, but lower capacity. The real monsters are ferries like the ones running Norway to Denmark on Color Lines in Europe, they carry way less passengers, but huge numbers of cars and big trucks. They have cabins, bars, restaurants, and entertainment, not bench seating. The 2 biggest are almost 75000 tons, but they are doing trips almost a full day long and pull 20kts.
I hadn't noticed the new ferries are actually longer, and heavier...thanks for pointing that out. Wonder why that is, if they are carrying less...were the Barberi class perhaps considered 'overloaded' at full capacity?
Those big Euro ferries are almost like ocean liner's...some even go overnite, and offer staterooms.
The largest ship I was on, that at one time did carry a few cars in its "garage", was the now retired RMS QE2. It was close to 70000 GRT. It is now serving as a hotel in Dubai.