I wouldn't expect UDRP to allow a trademark holder to take down a site critical of the holder; I that's a legitimate use of the trademark, even if it's not approved or desired.
However, that's not really what most companies are worried about, they're worried about phishing or scams or misleading sites with their name; UDRP should allow those to be taken down fairly easily, although the question is always if it's less expensive to register the domain or to leave it unregistered and dispute it if it's misused.
