Andrew Exum is not a Seymour Hersh fan:
My theory is that Hersh's journalism is a little like a 12-gauge shotgun. He just lets it go, and something is bound to hit the target. But each year, it seems, another inch is shaved off the barrel, so the shot group gets wider and wider. Over time, fewer and fewer pellets actually hit the target, but such is his reputation that people only remember the articles of his that actually exposed something new and none of the articles that, in retrospect, turned out to be just crazy talk.