I experimented with it briefly and even their provided example, despite claiming it works under IE, did not work properly under my copy of IE6, even after significant tinkering. It was quite nice in Firefox.
However, I’m a fan of this idea, at least philosophically, for a number of reasons.
XSLT allows a true separation of presentation and content, unlike XHTML/CSS2 which AFAIK still relies at least partially on the HTML markup to dictate page layout.
I’d like to see this project mature into something very powerful and universally useful. Anybody here toyed with it at all?