I travelled 11-19 Dec 2010 on Viking Legend's Christmas Market Cruise on the Danube. I wish I'd read previous reviews...particularly the one which spoke of the ship breaking down. We experienced the same. On the first day of sailing the extraction pumps failed and flooded all the bathrooms, then within an hour, the power went out and the boat stopped. As we were doing the Vienna to Nuremburg "up river" cruise...we started floating back down the river. The rest of the "cruise" was bus trips...some 4 hours long to reach our ports. The service staff was very accommodating and I'm sure the company was out quite a bit of money (extra bus expenses, providing lunches in local restaurants rather than on board, an overnight in a Nuremburg hotel the final night), however, we were out the experience promised. The company offered a 30% discount on a future cruise (apparently worth approx. $550), if used within a year, as compensation for us. My travelling companions were on a once in lifetime trip...there will be no compensation for them. As for me, I may do another river cruise, but not within a year.
I did not think the food was very good. Particularly the dinners. The service, again, though was very good. The rooms were adequate. The excursions were nice, though shortened. Apparently there are issues with the "green" engines. I would not risk this boat again!