I agree with "cruises two" that a cruise on the Diamond Princess is something to avoid. It was not long after departure that many of us renamed it the "Rhinestone" Princess.
We started off with a virus running rampant throughout the ship. We could not serve ourselves at the buffet; waiters served the items we pointed to. Even with that inconvenience, the buffet remained the best eating place throughout the trip.
Service in the restaurants was generally poor to terrible. A before-dinner drink was almost impossible to get. I ordered bourbon and water one evening, and shortly received a bottle of Perrier. I asked about the bourbon. It arrived within minutes in a tall glass without ice. I gave up at that moment and took ice from my water glass and mixed my own drink. My wife got the same treatment the next evening when she ordered a rum and coke.