Novice question about Output class

[eluser]Unknown[/eluser]
Hi,

I am a novice in CI and i have questions about some solutions, the first is:

I have a function like this in my controller:

Code:

function testAjax()
{
    $this->output->set_header('Content-type: text/xml');
    $this->output->set_output('&lt;?xml version="1.0" encoding="ISO-8859-1" ?&gt;<root>content</root>';
}

but i know i can do somethink like that:

Code:

function testAjax()
{
    header('Content-type: text/xml');
    echo '&lt;?xml version="1.0" encoding="ISO-8859-1" ?&gt;<root>content</root>';
}

the second solution use only php core functions.

Do you agree that the second solution is better (faster, portable)?
Is there any motive to use first solution?