We cruised on the Viking Danube from Amsterdam to Budapest. Viking were responsible for airport to ship transfers. At both ends their staff (crew) put us in a difficult, unpleasant situation so much so that it detracted significantly from our overall enjoyment.
There were other, lesser disappointments. They claim they have WiFi, but it operates at less than half of dial up speed, if at all. Very frustrating when we were planning to use it to keep in touch.
One of their evening "lecturers" was about as accomplished as a grade 8 student.
On a positive note, food service was excellent, the ship was comfortable and the crew, with a few notable exceptions, accommodating.
When we complained after our return ,they offered us a small discount on a future cruise. We will not choose Viking again.