My husband and I, together with two friends, were on the Elegant Elbe cruise in June, on the very new Viking Astrild. We were VERY lucky that the river level cooperated throughout our tour. The Elbe was very low during the weeks prior to our cruise, as well as the weeks after (low enough that Viking has had to cancel some July sailings). But thanks to some rain we were able to sail without major issues (however we had to use umbrellas during some of our shore excursions). We could not board the ship in Melnik as provided in the original itinerary, but instead boarded the ship in Decin, about half an hour away. Not a problem, as Decin has its own interesting sights to see. The Czech river authorities released some water from a nearby lock before our cruise to give the ship a "push."
As mentioned the Viking Astrild is new (I believe we were on its 7th sailing) so everything was in great condition. The food was very good; I can't recall having any bad food, although I didn't particularly enjoy the German dinner since I don't really care for German food.
The crew members were excellent, always smiling and eager to please. The program director Viktoria Muller was very well organized and made sure that everything went like clockwork.
As expected the cabin is a tight squeeze. There is barely enough room to walk around. However there is not much that can be done about that for this kind of ship, unless you want to pay a fortune for a suite. I found my bed and pillows not very comfortable; not firm enough for me. But firmness is a matter of personal preference and others told me they were comfortable.