We cruised the Viking Odin in September 2012 on the Danube from Nuremberg to Budapest. The cruise took us to places we had wanted to see. Our room was comfortable and well kept by housekeeping, the ship was very nice and the staff was very good especially the Cruise Director Joe, the front desk personnel and the hotel manager. The dining room staff was very attentive.
The daily excursions gave you an overview and we used receivers connected to the guide -- an excellent tool. For the most part the on-shore guides were knowledgeable and interesting. The 4 or 5 additional excursions could not be signed up for in advance of the cruise but these were quite good especially the Mozart-Strauss concert and the Danube Gorge. Why was the sign up not offered prior to sailing is a mystery.
Dinners in the Main Dining room were extremely noisy because all 190 guests were present at the same time making it difficult to have conversation. The dining room was crowded with armchairs that made it difficult to get in and out. Food was good but not exceptional. We did not purchase the wine & spirits package because wine or beer was provided at lunch and dinner and while it was built into the cost of the cruise, it was not worth it. We (6 of us) would have preferred to pay as you go instead. The evening entertainment consisted of a few local performers or a lecture by one of the staff, and there really was no space on board for much of anything. We were often linked up with 2 or 3 other Viking vessels visiting the same cities and used each other for transit to shore.