While I'm led to believe its likely just a design choice, is there any advantage to initializing properties in PHP to an explicit
protected $_foo = null;
protected $_bar = null;
protected $_baz = null;
protected $_array = array('a', 'b', 'c');
protected $_boolean = true;
protected $_foo = null; protected $_foo;
are completely equivalents.
As for me great choise is
null, if it will
It helps you to see default values quickly, helps code be self-documenting
Don't initialize array by
array() seems to be bad idea because you can't use some function (ex.