We took the Viking Delling cruise on the Danube (Nuremberg to Budapest) in July, 2014 and loved every minute. We were so impressed we decided to take the Rhine cruise last month. Where the food on the Delling was always excellent and regional dishes were featured, the meals on the Hlin were disappointingly repetitious, with generally over-cooked meat. It was especially bad on Friday, when the "special German dishes" of weiner schnitzel and sauerbraten were both so over-cooked and tough, they were just plain awful. On another evening , ahi tuna was cooked till it was uniformly gray.
Entertainment on the Delling was, as we remember, very enjoyable, with a good deal of diversity. The piano player on the Hlin, while (I'm sure) a fine musician, may have modeled his performance on Bill Murray's "Nick the Lounge Singer" bit on SNL. Flourishes abounded, making every tune sound like every other. We did not "hang out" to listen to him.
The shore excursions were fairly enjoyable, particularly the tours of Amsterdam, the Kinderdijk Windmill, Marksburg Castle, Cologne, Strasbourg and Colmar.
However, the Heidelberg Castle tour was a total waste of time, our guide was not good, and the town is merely one very long street of nothing-noteworthy shops, in which we had no interest. The excursion to the Black Forest, while picturesque, was mostly geared to trying to encourage us tourists to buy cuckoo clocks. The demonstration on making them was so crowded, we couldn't see or hear. Finally, I think it would have been nice to be given some information about Basel, rather than being just left on our own, since the Tinguely Museum was closed on Monday when we tried to go.