I would highly recommend Vantage River Cruises http://www.vantagetravel.com/trips/riverTours.asp for the itinerary you mention. We took the same cruise this past summer with them and loved it. Many informative lecturers for every port, wonderful meals both on and off ship, and terrific staff. We had looked at all the companies you mention plus Viking River Cruises and chose Vantage and would do it again.

Cynthia & Ivan Pomona, NY