We just returned about a week ago from a 7 (?) night cruise on the Rhine on the Viking Hild.
Our first trip to Europe. What a wonderful experience.
The ship/cruise director Mathias, is about as good at his job as anyone we've ever seen. Super friendly, upbeat, informative, humorous, fun, etc. ... but so was everyone else. You get the feeling they all like what they do and they all get along.