it is said that Itachi's susanoo makes him invincible because of the combination of Yata mirror and Totsuka Blade, But Madara has a complete susanoo which is also quite strong. I am not sure whoz susanoo is stronger.
I'd go with PS since Madara is actually capable to sustaining it for more than 2 minutes, also he has the ability to cover other things with it such as the Kyuubi.
I'd go with PS since Madara is actually capable to sustaining it for more than 2 minutes, also he has the ability to cover other things with it such as the Kyuubi.