The old buildings have the usual old building problems, including hearing when your upstairs neighbor has gas or is feeling amorous. The newer concrete ones are much better, but entirely devoid of character. If you have millions, you can buy 49% of a house and get away from it all.

On balance, my experience of Switzerland was not particularly quiet, but then I mostly worked in urbia and lived in suburbia. The mountains are lovely and still, but there's not much tech work going in the forest.