I enjoyed many aspects of my Viking "Grand European" bus tour.
Which basically means I enjoyed the European towns we visited by bus. Viking offerred us a really sweet deal on their November "Grand European" river tour. Unfortunately they failed to mention to us that their boats couldn't sail due to low water levels on all the rivers we were supposed to sail, the Rhine, Main and Danube, and that we would be traveling far away from these scenic rivers, by buses.
I take particular umbrage at the fact that they booked us knowing full well that the rivers were unsailable, and had been since early June, but never told us.