Of the river cruises, I would say a hearty "aye". Besides being a lot more intimate than the open sea monsters, if there is a problem, dry land is always close by. It was not an option for some of the horror stories we have heard about Carnival and others. Of course, these immense vessels have elevators, but do they have small golf carts (or crew powered pedicabs) to motor around their quarter mile length?
Also: what might be the cost be of these floating hotels, or is it "if you have to ask ..."?