Norman Walsh has some words to say about RDF in RSS on his new weblog:
My problem is that "almost RDF" formats are a pain in the ass, just like all the other "almost" formats you've ever encountered. Yes, the transformation to RDF is easy with XSLT, but it's still an extra step.
From my perspective, the added complexity of RDF in RSS seems pretty minor and the payoff is less irritation for me. I call that a win. But I'm prepared to believe my perspective is a bit skewed.
It's worth checking out how Norman runs his weblog since it includes all kinds of juicy docbook, rdf and xslt goodness.