Viking cruises ruined our trip early this summer, In Budapest a Viking cruise boat killed all except seven people when colliding with a South Korean chartered boat. Later on the Main a different Viking boat was not tied down properly and broke one of the locks on the Main stopping all traffic between the Rhine and the Danube. Their crews are underpaid and not properly trained. Avoid at all costs!
https://www.usatoday.com/story/travel/news/2019/07/06/hungary-death-toll-danube-river-boat-crash-rises-27/*******001/