My late wife and I cruised Budapest/Amsterdam in 2018. Our final choice of operator was between Avalon and Scenic. We chose Avalon because we summised there would be a broader demographic of nationalities compared to Scenic which, as an Australian brand, would possibly have had a greater proportion of Aussies and Kiwis. Since then I believe Scenic now attracts a more diverse range of nationalities and is popular with N. American cruisers.
As for Avalon, we loved it, it was perfect. I particularly liked the beds being across ship rather than parallel. We could lie in/on our bed looking straight out, through the large sliding windows, at the world passing by.
Avalon had included tours in each city and special busses for pax with mobility issues with tours adapted to suit.