Popular vs Neglected in Competitions

[frederic]

What do you think would do better in competitions? The famous pieces that everyone plays because more people (including the judges) would enjoy them...or the less familiar music so that the judges have a more difficult task in judging them.
Compare the Tchaikovsky Concerto to the Mozskowski Concerto for example. They're both beautiful concertos. One's obviously more famous. But they are both very similiar in many ways. What would be a better choice for a competition?