15 days, started in Amsterdam and ended in Budapest. All in all, an enjoyable experience, wait staff was excellent (thanks Martin and Jana) and with one exception, food was great. Cabin was clean and well kept. Beds ok, toiletries ok, hair dryer ok, no exercise room though. Clean towels morning and evening if needed. Had both a 110 and 220 plug in the room for recharging camera batteries. Managed to fit the empty suitcases in the closet, but if they don't fit, the crew will store them in another part of the ship. One note of caution, rooms 214 and 215 are right under the gangplank when docked, and depending on which side the ship is docked on, your view will be obstructed while docking, you will also be entertained by noise from some sort of pump kicking on and off almost continuously.
Shore excursions were good although some of the local guides were a bit dull, but with the headsets that are issued you can wander and explore quite a distance from the tour guide and still hear every word without having to be withing earshot of the guide (Sonnenbrunnen , Vienna, in winter probably isn't worth the tour price, you can catch the public transport and pay the 12-14 Euro entrance fee, rather than the 44 Euro tour price fee if you really, really haven't seen enough palaces yet, although in summer it's probably very pretty). With the exception of Vienna, and Koblenz, there was sufficient time to explore on your own at most stops.
My main complaints would be the Program (Cruise) Director staff, none had the personality I would look for when hiring for this position. There were a few nightly activities organized by the Program Director (i.e. glass blowing, local music demonstrations) but other entertainment activities weren't carried out as well as they could have been, any prizes were generally a bottle of Viking Champagne, which in all honesty, wasn't very good. The raffle also was disappointing, if memory serves, raffle items included Viking T Shirts, Sweat Tops and Caps, a jar of mustard and Viking Champagne, in my view, non worth the price of a raffle ticket (if anyone from Viking reads this, you may want to consider caps and Ts as freebies, great low cost advertisement). My second complaint is the internet connectivity on board. More often it did not work, even when in the middle of a city. I was counting on the internet to make hotel and train reservations after the cruise, but simply couldn't get on line, so ended up paying walk in rack rate at a hotel in Budapest instead of the internet rate, also missed out on the sale of an unexpected stock jump that would have paid for half of the cruise because of non access to the net.
Excluding the above negatives, we enjoyed the cruise and will in all probability take another.