Again, you will have a great experience with AMA and with Deilmann. It mainly depends on what you put your emphasis on. If you say I want a perfect dinner experience go for Deilmann. If you want the perfect itinerary AMA might be the better choice.
Itīs up to you.
Steamboats, I don't quite understand why it's an "either/or" proposition...
I know that these river cruises can't be all things to all people, but who among us doesn't desire excellent accomodations, wonderful shore excursions, and delightful cuisine for their adventure?