List Posts, Order by Rating

How do you list posts in order of rating? A similar plugin used a custom query (see below).

<?php // ORDER BY LIKES
    $args  = array(
        'orderby' => 'meta_value',
        'order' => 'DESC',
        'meta_query' => array(
            'relation' => 'OR',
             array(
                'key' => 'Likes',
                'compare' => 'NOT EXISTS',
                'type' => 'numeric'
             ),
             array(
                'key' => 'Likes',
                'compare' => 'EXISTS',
                'type' => 'numeric'
             )
         )
    );
    $args = array_merge( $args , $wp_query->query );
    query_posts($args);
?>

What is the query that we should use? Please let me know… Thanks.