Having returned from the April 19-May 2, 2012 Passages to Eastern Europe (Budapest to Bucharest), we recommend it. Weather was good and the cruise scenic and the Primadonna a very comfortable and attractive boat (soon going out of service). This was our third time in Budapest and so we took advantage of the morning tour for orientation and then sought out two art museums. Overall, the walking was moderately challenging, but never overwhelming. (We hate cobblestone with a passion.) Local guides were good. And we enjoyed the "quiet boxes" to hear the tour guides (although they need to be reminded to talk clearly into their devices to be heard well).
About one-quarter of the passengers , we among them, took the Transylvania post-cruise extension. That gave us a ride through Wallachia into Transylvania with its Germanic background. There was a modern castle and a medieval castle along the way. We toured Brasnov in the morning and returned to Bucharest. Not enough people showed interest in the full-day bus ride from Bucharest to and from Constanta. That would have meant seven hours on a bus in ordinary traffic for about a three-hour visit to nothing spectacular just to say we looked at the Black Sea. That would have cost approximately $100 per person. However, May 1st happened to be Labor Day in Romania (as in much of Europe. Museums and attractions were generally closed, but stores and restaurants were open because it was a touristic kind of day. Every Romanian who does not get the day off travels somewhere, thousands of them to shore sites. Traffic was impacted as it was on the 30th, and we could not imagine 165 miles of shore traffic the next day just to say we saw the Black Sea. We collectively engaged a guide for a two-hour walking tour of Bucharest on May 1st for 10 euros apiece. She was very knowledgeable and communicated well.
We had the cabin 208, nearest the exit, reception lobby, and opening onto the skylit atrium. And we were never discomforted by activity or noise. We were amused to find that the reflective windows made our cabin (which everyone walked past) virtually invisible from outside by day. When there was less light outside, however, the cabin became visible.