I don't remember the exact quote, but when asked about the CCTV design Koolhaas said that if you design and aim for height, the record will eventually fall. So instead it's better to design original/unique to give a building greater longevity and recognition.

The Burj Khalifa just opened, and it's the worldest tallest building, but there is nothing about it that is architecturally striking. Dubai really is the vanity capital of the world.