I was asked to make a new post on this topic. Hope of interest.
As I very much enjoyed my river cruise in April cruising the Danube between Passau and Budapest, I have taken the plunge and have booked the full Danube cruise on the Amadeus Brilliant which will go from Passau all the way to the Danube Delta and back to Passau. Does anyone have any feedback on must see attractions in Belgrade, Vidin, St Gheorge, Rouse, Svishtov, Novi Sad and Vukovar? Also is it worth going to see Bucharest and Constanta which is offered as an option from one of the Romanian ports?