[pluma]

I'd use "es" because it refers to the experience of being in Switzerland rather than the country itself.

But Switzerland is another example of a country that is typically used with an article. Consider the sentence "Ich fahre nach ____" with a country name. It doesn't work for countries like Switzerland ("nach Schweiz" sounds wrong, you'd instead say "in die Schweiz" -- same as "nach Kongo" vs "in den Kongo").

[schoen]

Thanks! Can we force the sentence to be about the country itself?

- Was meinen Sie über die Schweiz?

- ____ ist schön. / Ich finde ____ schön.