We have been in n many ocean cruises, and this was our first river cruise. Based on this experience, we are "hooked" on river cruises. We took the Grand European tour - Budapest to Amsterdam.
We loved the small number of passengers, personalized service by all staff, shore excursions.and fellow passengers. We are retired, and most passengers were 50 or older, well traveled, and interesting.
I have problems walking very long distances and standing for long periods of time. My husband, on the other hand is very athletic and active. There were tour groups that fit both our needs. There is a leisure group that is slower and avoids multiple steps and more strenuous terrain. Tour guides were excellent and knowledgeable . If you don't like group tours, the concierge is very knowledgeable about alternatives - hop on hop off buses, etc. I enjoy exploring on my own and met a fellow passenger who liked the same things.
Cabin was small, but well designed and very comfortable. We were only in cabin to sleep, so small size was not a problem for us. High end toiletries and great housekeeping.