XSLT guarantees XML, though not necessarily XHTML. TT2 doesn't guarantee anything other than "text". It also has a HTML output method, which can help with buggy browsers (read: Netscape 4), and offers some guarantees.

In reply to Re: Re: XSLT vs Templating? by Matts
in thread XSLT vs Templating? by Masem

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":