What we wanted - cruising down the river with views from our balcony. What we got - bus trips and views of other ships docked cheek by jowl.
The Danube has been in low water state for MONTHS apparently and so each cruise line has restricted the number of ports of call and anchored for days in some, essentially just providing an hotel for the night and bus tours for the days.
We were supposed to sail from Budapest to Nuremberg but ended up with less than half of that ( and mostly tied up at dock at that!)
Good rooms with nice balconies except most of the time one was tied up to another boat, looking at their balcony rooms, looking at us!
We stayed away from conducted tours, preferring to explore by ourselves at our own pace and not part of a "flag group"
Due to low water this was a free option, with many going because it was free and not because they were music lovers. Crowded, uncomfortable seats yet a fine concert despite this.
Did our own thing. Especially enjoyed tram ride to top of castle hill.
Due to low water had to bus to Passau and found walking tour a bit slow so did our own tour. Nice town but not worth a second look. Only did it because other cities were cancelled.