We enjoyed the cruise immensely. There was one major thing that we should have payed more attention to. First we had a great time in Budapest , our embarkation point; however, we spent maybe a couple of hours in Amsterdam, our destination port (at the airport). To do over we would have stayed a day or two in Amsterdam (and not part of the extended tour).
The cruise itself was great. Good food and excellent service by both the cabin attendants and the wait staff. Some of the land tours were a stretch--seemed like the tour guide was wasting time; but overall they rated very good.
Take advantage of some of the optional tours-- The Hungarian Horseman, Schonbrunn Palace in Vienna, the Mozart Concert, Rothenburg ob der Tauber (a must see) and the BMW factory are all worth the extra money.