Advantages / inconveniences of heredoc vs nowdoc in php

heredocs
1. heredocs text behaves just like a double-quoted string, without the double quotes.
2. Quotes in a heredoc do not need to be escaped, but the escape codes \n linefeed,
\r carriage return, \t horizontal tab, \v vertical tab, \e escape, \f form feed, \ backslash,\$ dollar sign,\" double-quote can still be used. Variables are expanded, but the same care must be taken when expressing complex variables inside a heredoc as with strings.

Example :

$myname='Tikku';
$heredoc_exmaple= <<<HEREDOC
\\n ,\\r ,\t ,\r ,\\v ,\\e ,\f ,\\ , \ ,$89 ,$ , $myname , ' , \$myname ,  \" ,\'
HEREDOC;
echo $heredoc_exmaple;

//OUTPUT \n ,\r ,   , ,\v ,\e , ,\ , \ ,$89 ,$ , Tikku , ' , $myname , \" ,\'

nowdocs
1. nowdocs text behaves just like a single-quoted string, without the single quotes.
2. Quotes in a nowdocs do not need to be escaped.Variables are not expanded in it.Advantage of nowdocs is embedding PHP code and escape codes without the need for escaping.

Example :

$myname='Tikku';
$nowdoc_exmaple= <<<'NOWDOC'
\\n ,\\r ,\t ,\r ,\\v ,\\e ,\f ,\\ , \ ,$89 ,$ , $myname  , ' , \$myname ,  \" ,\'
NOWDOC;

echo $nowdoc_exmaple;

//OUTPUT \\n ,\\r ,\t ,\r ,\\v ,\\e ,\f ,\\ , \ ,$89 ,$ , $myname , ' , \$myname , \" ,\'

Syntax: A nowdoc is identified with the same <<< sequence used for heredocs, but the identifier which follows is enclosed in single quotes, e.g. <<<'NOWDOC'. All the rules for heredoc identifiers also apply to nowdoc identifiers, especially those regarding the appearance of the closing identifier.

Nowdocs are to single-quoted strings what heredocs are to double-quoted strings. A nowdoc is specified similarly to a heredoc, but no parsing is done inside a nowdoc. The construct is ideal for embedding PHP code or other large blocks of text without the need for escaping.

http://php.net/manual/en/language.types.string.php#language.types.string.syntax.nowdoc

In other words:

$foo = 'bar';

$here = <<<HERE
    I'm here, $foo !
HERE;

$now = <<<'NOW'
    I'm now, $foo !      
NOW;

$here is "I'm here, bar !", while $now is "I'm now, $foo !".

If you don't need variable interpolation but need special characters like $ inside your string, Nowdocs are easier to use. That's all.