That's a rather bold statement to make. Windows users, for instance, see a tremendous speed bump in going to 5.5 (http://blog.syntaxc4.net/post/2013/06/20/php-5

That's a rather bold statement to make. Windows users, for instance, see a tremendous speed bump in going to 5.5 (http://blog.syntaxc4.net/post/2013/06/20/php-5-5-0-for-windows-released.aspx http://blog.syntaxc4.net/post/2013/06/20/php-5-5-0-for-windo...). Obviously going the "there is/isn't performance gains" flamewar route alone is a conversation nobody would win. So I would through this out there: If you have the capability to move to PHP 5.5, because there aren't performance penalties, you should - if for no other reason than it'll help you stay ahead of the PHP EOL sythe.