Best = US/UK. I don't see how this can be disputed really.
Worst = Asian countries (all of them). I know Germany gets a bad rap but
they're like Chevy Chase bouncing off Steve Martin in their prime compared
to Asian comedy.
Special awards go to Iceland/Sweden for being small but disproportionately
funny (if morose), Australia/NZ/Canada for being about half as funny as the
US/UK and Spain for being consistently surreal and sweary.
The concept of French farce is not funny to anyone other than the Parisian
bourgeois.
I've never seen Russian comedy. Might be hilarious.