People said that about XHTML2. People said that about Betamax. New doesn't always equal better.
At the moment, there's precious little reason to even think about using HTML5. Inline form validation for non-critical forms is one of the very few advantages it offers for the time being. A short and easy-to-remember doctype is the other But the fact that some mainstream browsers don't natively support HTML5 features means that using them now is either (a) doomed to failure, as some people won't be able to use your site, or (b) extra effort, putting workarounds in place to make sure they can. Neither of which seem like good strategies.
What HTML5 doesn't offer is any kind of rigid enforcement of what a lot of people here would consider 'good practice'. That doesn't mean that you can't do the right thing, it just means that you don't have to. It introduces a lot of new elements that don't seem to be particularly necessary, and leaves in others that it should have taken out.
But this isn't the place for a detailed discussion of HTML5, there's plenty of that already going on.