向我的订阅者发送大量电子邮件的最佳方式(密件抄送还是PEAR邮件队列?)

我需要给5000个订户发邮件。 最好的方法是什么?

1)使用密件抄送?:

  $from_addr = 'myemail@example.com';
  $mailing_list = 'sub1@example.com', 'sub2@example.com', 'sub3@example.com0;
  $message_subject = 'this is a test';

 `$headers = array ("From" => $from_addr,
                    "Bcc" => $mailing_list,
                    "Subject" => $message_subject);

  $smtp = Mail::factory("smtp", array ('host' => "smtp.example.com",
                                       'auth' => true,
                                       'username' => "xxx",
                                       'password' => "xxx"));

  $mail = $smtp->send($email, $headers, $message_body);`

.

2)使用Pear邮件队列?