The JSP Document syntax (the strict XML syntax ) is intended for the containers to use internally as an intermediary representation, or to make it easy for code to auto-generate JSP pages by serializing an internal DOM.
It is not intended for humans to hand-code or maintain. [ July 13, 2006: Message edited by: Bear Bibeault ]
In older versions of JSP the <jsp:getProperty ../> tags were referred to as the XML Sytnax tags (as opposed to <%=beanName.getProperty()%>).
It is now possible to create an entire JSP page under a strict XML doctype; something different entirely.
Since you are asking about the difference between 'directives and xml syntax', I suspect you may be asking about the difference between <%@ page include...%> and <jsp:include .../> tags.
Please elaborate on your question so we understand what it is that you're asking.
The OP needs to let us know whether he's inquiring about the difference between JSP Pages and JSP Documents, or the difference between directives and actions.