Nuremberg to Budapest. It was awesome. I’m glad I didn’t have to pay. Would love to do it again.
On ours, there were one or two excursions ant each port included as part of the cost. Usually the guided city tours. Like an ocean cruise, you can choose to do your own thing instead.
Hard to compare it to an ocean cruise. There’s always land to see, fewer food options, but the food was very good. You don’t really need to entertained by stuff on the ship because you’re in Europe, so something worth seeing in every city you stop in. That’s probably my favorite thing. Too many cruise ports are basically tourist traps now. On a river cruise, you’re stopping in cities, so anything you want is there.