I'm not as inclined as Michael to find fault with Judge Fallon's decision to declare a mistrial. The jury had deliberated for eighteen hours over three different days, and Fallon had issued an Allen charge to the jury (over the plaintiffs' objection), directing them to try especially hard to reach agreement and that each juror consider changing his or her mind. Such instructions (sometimes called a "dynamite charge") are controversial because some view it as coercive. I would've let the jury deliberate another day or two myself, but the attorneys were careful to avoid criticizing Fallon's decision publicly—though that may reflect the reality that there's no profit in angering Fallon in critiquing unreviewable decisions.
(The fact, incidentally, that it was the plaintiffs who objected to the Allen charge suggests that plaintiffs' lawyers were committing some serious spin when they expressed to the press disappointment with the mistrial declaration.)
Here's a link to the Wall Street Journal article ($) Michael refers to, which has been updated for this morning's paper from yesterday's web version.