Started trip with pre-trip in Prague, Hilton great but Viking staff generally confused there. Once we got on boat staff and trip looked much better. An included tour everyday. Local guides, whisper sound systems included so everyone could hear, and Viking staff that knew exactly what they were doing. All the staff seemed dedicated to making sure you had a good time.
I can't say enough about wearing good shoes. The cobble stones are wicked and exhausting. Most of the tours are through the narrow town streets with frequent stairs. That is just the way of European towns.
The food was excellent with vegetarian offerings at every meal and a variety of alternatives if you didn't like the menu choices. I never heard anyone complain about the meals. On the other hand, it took four flights of stairs for me to get from my room to the dining room to be sure you are in shape for this cruise.
For things to bring clothes, people loved the shoes, scarves, paprika, and sweet mustard. There are lots of cute clothes and dolls for kids and Coo Coo clocks.
Do try some of the local sausages and beer along the trip.