Viking sales task was not forthcoming about our cruise ship's location with respect to the Passau train station--we took a taxi though it was only a five minute walk. But all other encounters with Viking personnel were thoroughly professional. We got a warm reception on our arrival at the ship from the ever-helpful front desk personnel. The bottle of sparkling water in our cabin was free, and a further free bottle appeared each day. A plate of fruit and marzipan also greeted us. One could and did sit in our cabin's wide picture window through which we took many a photograph as we cruised along. (Its one downside came when we parked alongside a second Viking ship and cabin window faces cabin window.)
A large cabin with plenty of space to walk about, store clothes and work on the computer. What! Twin beds equipped with twin bedding! And the wifi internet connection worked painfully slowly when it worked at all.
Dinners and dining companions were five star and first rate. I still remember the three-item pumpkin appetizer that preceded the venison. Presentation matches the quality of the food. Have multiple allergies and digestive problems? We don't. But the maitre'd worked with a new-found friend of ours on a nightly basis to develop a special menu for her.
Back in the cabin, want a second pillow to put under your legs? Just ask.
Daily free tours which other cruise lines charge for. Presentations were excellent with no attempt made to sell us gold or a rug. Presenters suggested activities and places to visit during the free time on each tour. Which is how we came to have hot chocolate (mine laced with chili) and Sachertorte at Demels in Vienna (where your table is separated by a plate glass window from the pastry chefs in action.)
An optional overpriced tour is available each day also. Skip the latter; a Hungarian horse show priced at $44E per person lasted exactly 20 minutes. It was a great show, but 2 euro per person per minute is a tad excessive.
Would we do it again? Never in winter--and yes, we were marooned at the airport for a day on our return.