Facelets: Duvida sobre root

Front-end
#1

galera qual a diferença, e porque usar um ou outro, qual devo usar??

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:ui="http://java.sun.com/jsf/facelets"
      xmlns:h="http://java.sun.com/jsf/html">
    <body>
    ...

ou direto com <ui:composition??

<ui:composition xmlns="http://www.w3.org/1999/xhtml"
                xmlns:ui="http://java.sun.com/jsf/facelets"
                xmlns:h="http://java.sun.com/jsf/html"
                xmlns:f="http://java.sun.com/jsf/core"
                xmlns:a4j="http://richfaces.org/a4j"
                xmlns:rich="http://richfaces.org/rich">
#2