it was so long ago that my experience would not be any use to you. I did like Berlin. When I was staying in Munich, I visited Salzburg, Austria as a day trip and then went “home” to Munich that night. I’m not sure how much further Vienna is. I only passed through Vienna via train on my way from Prague to Venice.
Right now, we're looking at staying near Munich and moving around, hoping to get a day in Vienna. My mom is very fussy and so based on reviews, we think Berlin can be a miss for the family trip (we took her to London and Dublin, not a fan -- enjoyed Belfast and the Bath). Her least favorite city in the US is San Franciscan (I don't get it).
Who didn’t like London and Dublin — you or your Mom? I don’t think I’ve ever met anyone who would name San Francisco as their least favorite city in the US.
Taking your parents to Germany is a really nice thing for you and your sister to be doing? I hope you all have a great trip.