After Sean Carroll posted the video of the debate on his blog, I finally got around to watching it. We all have our biases, but I've seen some of Craig's debates where I thought his opponent performed poorly or (more commonly) the two interlocutors simply spent two hours talking past one another.
But this, I thought, was a clear and decisive victory for Sean Carroll. He presented a strong thesis that countered Craig's theistic viewpoint, and answered Craig's arguments directly and incisively. He repeatedly corrected Craig on cosmological issues (such as what the Borde-Guth-Vilenkin theorem actually says, which is something I have personally hammered home in the past) and did a fantastic job tying in the esoteric discussion of science and philosophy with more everyday concerns of meaning and purpose.
Craig, on the other hand, repeated irrelevant and rebutted arguments, often times repeating an argument without adding anything new or relevant even after Carroll had directly countered it. This could be my biases projecting, but I thought Craig looked comparatively (and uncharacteristically) disorganized and confused. Carroll sternly corrected Craig throughout the debate and the Q&A, with my favorite moment being Craig's attempt to claim that Alan Guth simply had some sort of personal desire for an eternal universe to be real; Carroll countered that no, it's because Guth is a scientist, that the BGV Theorem applies only to classical descriptions of space-time, and because Guth (like any good scientist) is looking for the best model to fit the data.
Frankly, the debate went just as I expected. Sean Carroll, as always, was a thrill to watch. He's not just a smart guy and a philosophically-conscientious physicist, but he's a great communicator and does a fine job of translating esoteric science into layman's terms and getting to the meat of why it all matters. While there was no direct cross-examination as there was in Craig's dismal performance against Shelly Kagan (and frankly, I suspect that debate plays a large part in why Craig shies away from that format), I'm confident that if there were it would have been even more drastic of a loss for Craig. This debate showed that despite his pretense of expertise, William Lane Craig is not a physicist but a theologian who is in way over his head. In any case, here's the debate in full: