You seem to be arguing against something I never said. I never said America wasn't the best country on earth. I simply challenged him to articulate objective reasons rather than just yelling we're the best with zero logic and reasoning.
With that said, I do believe America is the best country on earth. But not for what you stated. America is the best because of the American Dream. The idea that you can be anything you want to be if you work hard enough. Despite the fact it might not be equally accessible to everyone, there's still no other country that gives you as much opportunity as America. So yeah I definitely would not want to live anywhere else.