XSLT is a very powerful tool on itself, so I doubt that adding a framework into the workflow will have an improving effect if you just want to read XML and transform it into HTML. That is just the kind of job XSLT was invented for.
Maybe the not exactly matching Question XML Outputting - PHP vs JS vs Anything Else? gives an idea how XSLT works.
Edit @hakre comment: PHP supports XML/XSLT, no framework needed is what I say. If you follow the link I suggested you'll see that a transformation needs only 3 lines of PHP-code (beside XML data and XSLT script, of course). PHP uses the very fast and stable xmllib2/xsltlib library in the standard installation, no lib adding is necessary.
Edit @Kendall comment: XSLT is a w3c standard templating language. Why use another one which probably will be not as wide used, documented and supported? To hit the nail on your question: For the task you describe I can't recommend any framework over XSLT which is already built in PHP to use XML and display HTML using XSL transformation. Why putting an framework above instead talking directly XSLT? It's a language, not an API. Even versatility will be better.