The pace of a river cruise is sedate so that we had time to enjoy the countryside and fall colors as we sailed along. The city tour guides were enthusiastic and knowledgeable. The weather was also a bonus. It went from a light mist in Holland to sunny and warm for the rest of the trip. Our extension to Prague was a special highlight.
The small ship river cruise was new to us. We were able to get to know most of the passengers and all of the crew. Our cruise director, Gary, was especially helpful. He kept track of all of the people on excursions and was delightfully entertaining with his on board banter. Front desk personnel were always helpful and took extra steps to provide for special needs that came up.
There are more options available on a large ship but you are also spending a lot of time at sea and therefore need more things to do. The river cruise always had something interesting outside and the pace is slower.