I guess that depends on what you compare it to. Using iteration will increase its weight lineally based on the length of the string. Shorter it is, the better it will perform even compared to what is here. The longer it is, the worse it will perform, even compared to what is here.
Doing all that needs to get done, I would expect you'd see better performance on average using regex. Overall it'll be about the same. If I have a password of 'aaaa' and allow all rules to evaluate, than iteration will win. If I have a password of 'this is my passphrase which is quite long', than regex will win.
As of PHP 5.5, the MySQL library has been officially deprecated. It is recommended to move to either MySQLi or PDO libraries for your mysql connectivity. See here for help choosing which interface you prefer: http://php.net/manual/en/mysqlinfo.api.choosing.php