Are there any differences between get_object_vars($obj) and (array) $obj ?
Both seem to return the public properties of the object.
This is not exactly true.
get_object_vars is scope-sensitive and will return all visible properties excepting static properties regardless of their visbility. If you call it from outside your class, you'll only get the public members; from a derived class, you'll get the protected and public members; and from the class itself, you'll get all the members. The array keys represent the property names, and are not mangled.
The (array) cast returns, at least on PHP 5.3.0, all the object properties, public and otherwise. The name of the properties are mangled according to their protection level:
public: not mangled, identical to property namesprotected: key name for property starts with a *private: key name for property starts with the name of the classSee casting to an array for more informations.
I hope you'll be able to better understand which one is the most appropriate for your situation.