I wasn't trying to suggest Smack switch to another parser, I was only curious as-to why StAX was chosen 
(xml parsing can easily turn into a flame war lol)
You are correct, once SAX parser gets going, there's no stopping it! It vomits out nodes! So, if all you're after is a node or two from a giant xml, then SAX may not be as efficient since it must finish parsing the document.
There are other ways to write XML (good god, DOM is awful). JAXB is a nice one, it maps java objects to xml nodes and vice versa.