We were intrigued by the itinerary and opportunity to see a variety of places and things. (One previous cruise was the Castles and Cathedrals cruise from Basel.) The ship and crew from the Captain and Hotel Director down were totally involved with the passengers.
The Captain was often seen welcoming us back from our day's adventure and if you didn't talk with the HD or Tour Director once or twice a day, it was because you avoided them. The ship was immaculate and food outstanding - far better than the large Longships. We opted to spend an extra four nights in Berlin before the cruise and one extra in Warsaw at the end. We not only castles and cathedrals, but also a wide variety of other things including Auschwitz. We were concerned about low water, but it is a risk you take if you want to cruise the Elbe. One of the few down spots was the incredibly bad Sheraton in Berlin and poor Radisson Blu in Krakow. If you do the extension to Poland, consider hiring a private guide in Prague and Warsaw. Otherwise the tour is pretty much a drive by on the coach with a few stops.
Cabin was great. We saw no need to upgrade since only five nights were on the ship - others in hotels. (There was no difference in the type of hotel room.) This was confirmed when we got onboard as the windows on the first deck are much lower than on the Longships. It was only a short walk to the outside areas.