We were in Salzburg in the winter, and in a blizzard. It was quite pretty. That said, I'd like to see it in the summer as well.
We took the Panaramic tour which included stops in Werfen and Mondsee(wedding church). We enjoyed the tour very much, including my daughter who is not really a fan of the movie.
I know much about the Von Trapps having taken piano lessons from a man that knew them. They, themselves, used their notoriety to market their Vermont lodge. As far as the locals in Salzburg not appreciating the story/movie, I didn't run into anything like that. There are many movies and books that do not follow the "actual" story, to a T. Would people have enjoyed the movie if it had shown the VonTrapps leaving Salzburg via a train without the drama? Maybe. Who knows? I think if a tourist shows interest in Salzburg's and Austria's many other attributes, doing some research into the history and beauty of the country, there would should be no hard feelings.
Travelers should be aware that Austrians, like Germans, are quite reserved. Maybe some travelers confuse their reserved nature for dislike of SOM fans.