I always thought of Salzburg as a bit of a whore. It's very beautiful, but it just wants your money quickly and then wants you out of the place again as fast as possible. If you play music on a terrace - even for fun and friends - you are likely to be shooed away as they need that space to sell something to the next customer. My favourite towns in Austria are Linz and Graz. They are very different, but they are both very lovely provincial cities where people take their time a bit more. That can be good for buskers. Good luck Marion.