We have just returned from a wonderful cruise to Japan, South Korea and Taiwan on the Diamond Princess. We totally disagree with all the complaining reviews of the ship. We loved it. The food was excellent, the cabin better than expected and the bed extremely comfortable. All the crew at every level were friendly, welcoming and very efficient and helpful. The ship was smart and clean and we enjoyed meeting the other passengers.
We have been on many many cruises and, while we prefer small ships, we found that size was not a problem on the Diamond Princess. Though it was busy, we rarely queued at all for food in Horizon and were always able to disembark as soon as we wanted to except at the one tender port.
The downsides: We don't like fixed dining as the times are not convenient.
We never go on the ship's organised excursions as they are ludicrously expensive and one is herded around in big groups, wasting time waiting for others and then being rushed through the most interesting places. On this cruise we found it very easy to find our own way around, especially with the excellent advice of Luca the Destination Expert plus a great deal of our own research in advance. This was also much much cheaper - public transport was efficient and very easy to use.
We don't drink on cruises as the bar prices and service charge are far too high, especially given that drinks should be duty free,
We don't cruise for the shows. If they are good then that is a bonus, if we are bored we discreetly leave. We cruise for destinations we want to go to at a reasonable price and the convenience of not having to pack and unpack in order to travel around plus good food without having to search for restaurants in unknown places!
Good storage space, better than on many cruise lines, very comfortable bed, good balcony, bathroom fine and again, better than some we have had.