I don't have the wealth of experience that many do who have already posted. We have only done two river cruises so far - but our first (2017) was Uniworld's Castles Along the Rhine from Amsterdam to Basel, and it was wonderful in every way. We enjoyed it so much that we did another Uniworld cruise (Delightful Danube and Prague) last summer and hope to do others when it is safer to travel. We like the fact that Uniworld is all-inclusive (except for a few extra excursions) -- no nickel/diming, no surprises at the end. Tips are not required/expected (although we did tip our housekeeper and a