Has multiculturalism succeeded in Australia?

Unlike European countries, Australia is a country built on mass migration. In October, German Chancellor Angela Merkel declared that multiculturalism as a policy in her country was a failure. And just this weekend David Cameron said it wasn't working for Britain either. While some Australian commentators and politicians have questioned the success of multiculturalism in Australia, others believe it has been working extremely well. What do you think? What lessons can we learn from other countries?