Pluralism Vs. Multi Culturalism ?

Which do you favor?

"Pluralism allows for many different groupings but, unlike multiculturalism, does not try to impose one uniform status on all of them. It allows a thousand flowers to bloom, with minorities forming communities of faith, ethnicity or culture within a society — but under the overarching umbrella of a national identity to whose core values everyone signs up. It is only by having that overarching set of common values — monogamy, freedom of conscience, equal rights for women, freedom of expression — that a society coheres as a common project."

Are mono-cultural societies (Japan, Switzerland and others) more successful?

Is America a failed multi-cutural experiment?