How would you choose?

Had an interesting thought today. Going to phrase this question in the form of a story.

Let's say you're an atheist and grew up in an atheist household, you have never really known God and you really don't have any knowledge of any religion. You're walking down the street and the clouds break.

Before you stands God. You know it's God and he says to you "Worship me, my son." Then he disappears and the clouds close up.

You find yourself on a street. On the left hand side is "The Church of Man's Last Hope". On the right, "The Church of the Last Hope for Man." Both have similar tenents, with some slight changes, however, both claim the other is wrong.

Given that you know a God exists, how do you intelligently figure out which church you should attend?