That depends on perspective. I know people from other countries that claim European culture is the worst. What makes you right over them?
What makes you right in your belief that there is no superior culture?
It's a philosophical question, isn't it?
Or, we can apply a basic empirical test. The best culture is where people want to live. Given a choice, most people would rather live in a better culture than a worse culture. Individuals may have preferences and disagree, but movements of broad populations will empirically tell you where people generally want to go.
Where do people want to live? Is there mass migration from the West to the rest if the world, or vice versa? Do millions of people emigrate to the West, many risking their lives and die trying, or are there millions of Westerners clamoring to move to the likes of Saudi Arabia, Tanzania or El Salvador?