I disliked the reading on this one, and felt that it detracted more from the story than it contributed. I thought the ums, ahs, and throat clearing were just bad reading or editing. The voice acting on Lucifer and Satan were good, the woman was fine, but I disliked the protagonist. After reading this thread and seeing the glowing reviews, I gave it another listen.
After the second listen, I liked it less as it became clear that the stuttering was deliberate, as much of it felt unnatural and injected at points where there wouldn't be expected stumbles in conversation or the relation of a story. In addition, if it's being told by the protagonist, why is the protagonist affecting the voices of the other three? And when he affects their voices, why does he lose his stammer? If the reader wanted to better separate the protagonists's voice and the voices of the other characters, the transition words between characters ("said Satan" etc) should have been done in the reader's own voice without the stammer.
I'm glad others liked it, but I found the voice work to be a mixed bag.