McCain did not shine at this religious forum. Although the political pundits ceded him the advantage to his politicking in church, the religious equation is different. For instance, it was remarkable that McCain could speak to a pastor for an hour and not mention Jesus' name once or cite the Bible by chapter and verse. Obama, on the other hand, not only proclaimed Christ his Savior, but quoted scripture knowledgeably. As on other occasions, McCain shows himself to be tone deaf in faith-telling.
On the issue of abortion, in particular, Stevens-Arroyo notes that Obama was far more practical in his approach.
Obama demonstrated a respect for the role of theology, biology and metaphysics in determining precisely when this moment occurred. McCain had no such reserve. For him, the issue was without nuance or tolerance for differing opinions. Obama dwelt on the "pragmatic" side of the issue: What laws, policies and programs can be promoted to reduce the number of abortions? These after all were the steps taken by Clinton that began the downward trend in abortions. McCain reiterated the ideological side: He is against abortion, and like Reagan who saw abortions increase on this watch, did no more than deliver his opinion.
As Alan noted in comments here, the kind of opinion-mongering McCain engaged in is meaningless because Republicans have no intention of doing anything about abortion anyway. Obama's approach - dealing with policy rather than philosophy - might not have been received well at Saddleback, but I am quite sure the message was heard among those listening who are less convinced of either the the answer to the question or the relevance of such opinions to public policy.
In all, I find it interesting that Obama seemed to win on points here, even as McCain seems to be touted as the "victor". The backpedaling on whether McCain was ignorant of the questions beforehand - the whole "cone of silence" nonsense - that both McCain and Warren have been forced to engage in due to revelations that McCain was actually in a car on his way to the church, therefore given the opportunity to hear the questions beforehand is an important factor here. As with much else in this campaign, the usual narratives of McCain's alleged strengths (in this case, his ease in this type of forum; his readiness, even eagerness, to pander to whatever audience he is addressing by telling them what they want to hear) become disadvantages over time as we learn the stories told by McCain and his campaign are untrue. Like the whole "cross in the sand" story, it is a tissue of lies that might benefit him in the short run, but only bite him once it gets out there in the real world.