This was our first Viking river cruise and we almost certainly will do more. We took a Danube River cruise from Nuremberg to Budapest, with extra days in Prague before the cruise and Budapest at the end.
Embarkation was smooth and handled well. However, at the end of the cruise they really push you out of the rooms early. Everyone has to be out by 9 a.m. even though that count as one of the eight days on the cruise. There was some confusion and late buses on our last day.
The cabin was wonderful. We had a balcony but because of inclement weather most of the time on the river, we seldom used it except to take pictures. Cabins are extremely clean and incredibly well thought out. There isn't a lot of room, but it works well. Besides, who is going to spend time n the room when there are so many tours to take, places to visit, and good food in the shipboard restaurant.