Jamie's childhood preacher Charles Jacobs wanders in and out of Jamie's story over the course of the novel. Reverend Jacobs loses faith early on in the story, but he never gives up his obsession with electricity, and each time Jamie meets up with Jacobs, he learns a little more about the mad scientist's latest experiments, non of which really ring true, despite King's huckstering and hand-waving.
And then there's the ending. The ending of Revival would have worked for a 30 minute episode of The Twilight Zone or Creepshow, but in a 400+ page novel, it feels ridiculous. If you really want to know what happens, this spoiler-filled customer review at Amazon sums it up nicely.
I "read" the audiobook, which is narrated by David Morse, who does a fantastic job. I enjoyed the storytelling, but I never felt any tension and I can't think about the ending without shaking my head.