How to implement AJAX commenting in WordPress

I'm trying to 'ajaxify' commenting in WordPress using this tutorial Ajaxify WordPress Comments

Here is my PHP handler:

function ajaxify_comments( $comment_ID, $comment_status ){
    if( ! empty( $_SERVER['HTTP_X_REQUESTED_WITH'] ) && strtolower( $_SERVER['HTTP_X_REQUESTED_WITH'] ) == 'xmlhttprequest' ) {
        //If AJAX Request Then
        switch( $comment_status ) {
            case '0':
                //notify moderator of unapproved comment
                wp_notify_moderator( $comment_ID );
            case '1': //Approved comment
                echo "success";
                $commentdata = &get_comment( $comment_ID, ARRAY_A );
                $post = &get_post( $commentdata['comment_post_ID'] );
                wp_notify_postauthor( $comment_ID, $commentdata['comment_type'] );
                break;
            default:
                echo "error";
        }
        exit;
    }
}
add_action( 'comment_post', 'ajaxify_comments', 20, 2 );

And here is my script:

jQuery('document').ready(function($){
    var commentform=$('#commentform'); // find the comment form
    commentform.prepend('<div id="comment-status" ></div>'); // add info panel before the form to provide feedback or errors
    var statusdiv=$('#comment-status'); // define the infopanel

    commentform.submit(function(){
        //serialize and store form data in a variable
        var formdata=commentform.serialize();
        //Add a status message
        statusdiv.html('<p>Processing...</p>');
        //Extract action URL from commentform
        var formurl=commentform.attr('action');
        //Post Form with data
        $.ajax({
            type: 'post',
            url: formurl,
            data: formdata,
            error: function(XMLHttpRequest, textStatus, errorThrown){
                statusdiv.html('<p class="ajax-error" >You might have left one of the fields blank, or be posting too quickly</p>');
                                },
            success: function(data, textStatus){
                if(data=="success")
                    statusdiv.html('<p class="ajax-success" >Thanks for your comment. We appreciate your response.</p>');
                else
                    statusdiv.html('<p class="ajax-error" >Please wait a while before posting your next comment</p>');
                    commentform.find('textarea[name=comment]').val('');
                                }
                });
                return false;
        });
});

Every time I post a comment, I get: "Please wait a while before posting your next comment". Hoping somebody can tell me what I'm doing wrong?