Hi.
I did the Danube cruise last August. It was fantastic!
The included excursions are great on this cruise.
I don’t know anyone who did the Bratislava beer tasting. You will find that food-wise, there is nearly always a matching of food and alcohol to the location you are in as part of the dinner service, meaning missing the included dinner to pay to go elsewhere.. well, it wasn’t as popular.
We did the Vienna Residence Orchestra - https://viking.tv/tv/this-week-on-viking-tv/mondays/meet-the-vienna-residence-orchestra - definitely worthwhile even if opera or classical is your thing - there is a good mix of entertainment.
A couple we met on the cruise did the Prague day and enjoyed it.