1) part of the fun of visiting a location is local dining. eating on the river cruise ship takes that away.
2) they dictate how long you have.
3) debarking with 190 other people makes for making tours harder.
4) limited hours to book events.
pluses are
1) I'm not driving
2) not changing hotels every night
3) I get to watch the scenery as we move
4) ????