Yes, there’s still no XPath support in IE =/.
For me, the most reliable way to use document.evaluate in every browser is, sadly, via a library.
It’s called Wicked Good XPath and it’s a recent Google-authored rewrite of the old good JavaScript-XPath library. I’ve been using Wicked Good XPath since the release and have been really comfortable with it (well, not as much as with a native XPath support, but still).