We had a cruise cancelled at the beginning of the pandemic so we used the credit to take this longer cruise. Other than the awful Viking Air service, the cruise itself, especially the crew, was outstanding. The most enjoyable parts were extra shore excursions that were in very small groups, especially the "vigorous" hikes. However, I wouldn't call any of the hikes vigorous (and I'm 68 though I do hike frequently). A surprisingly fun event was sausage making in Regensburg.
We sat at the same table with the other couple that we came with each night with the same waiters who were fantastic. They knew our preferences whether it be juice or wine and often anticipated our next request. We've taken one other Viking cruise and this crew had a much better esprit de corps. They really wanted to serve.
The cruise lets you see a lot of Europe but only a short time in any port. This was at times frustrating as it was suggested to try the local beer but we had to be back on the boat before the pub/brewery opened. It is a good option to identify where you may want to return to.
The veranda suite is great so one of us can stay up and watch tv and the other read a bit and get to sleep. It also provides the space to get some work or journaling done.