I was referring to their system of direct democracy, not PR. So far as I know the Swiss use it the most, although Ireland and the State of California also make extensive use of referenda.
Maybe the Scandinavian countries are happy. Denmark is small and, so far as I'm aware, settled country. We've a nation of 60 million people split about all kinds of things. We have a thousand-year-old adversarial tradition. PR and its endless coalitions will drive controversy out of public life altogether -- the main three parties are already very close -- and will probably fuel extremism of all kinds.