Batman vs. Superman ... With Your Wife! Director Zack Snyder Chooses

Batman or Superman -- which one's gonna bang your wife when you're not looking ... is the question we put to the world's leading expert on the caped wonders.

Of course, Zack Snyder's directing the highly anticipated "Batman v. Superman: Dawn of Justice" ... so when our camera guy spotted him in Hollywood, he fired off a super series of questions about the heroes.

Who's cheap, who'd babysit, and best of all -- who'd you trust hanging out with your wife? Zack played along, answering all 3.

We trust he knew this was hypothetical, and not really about Ben Affleck and Henry Cavill.