Interesting discussion.
Main reason we like the YC is the ship in ship idea. One can use, enjoy and experience all the possibilities a big ship is offering. Including huge number of bars, restaurants, entertainment and parties. And on MSC especially an international mix of people.
On the other hand you go on your "YC ship " and enjoy an excellent service and the dignified environment there and escape from the crazyness if you like . For us for example the TSL gets a bit boring in the evening.
Obviously all depending of what people expect from there cruise experience.