The Devil to Pay was fascinating, but ultimately just a bit disappointing.
There were so many incredible questions raised regarding the nature of God and evil, and Sayers attempts to answer all of them, but in my opinion no conclusion was fully satisfying. The greatest question of the drama, I think, was asked by Mephistopheles: "and what, pray, would become of religion if there were no such thing as suffering?"
It is this question that plagues Faustus, and it is because of the suffering of others that makes his choices. Yes, he uses devils; but he does so in order to do good deeds. His works are good until (and this is no spoiler) he actually gives up his soul. The play fails to tell me, in my opinion, why we should be judging Faustus when he is using evil to accomplish good in a way that hurts no one but, really, himself.
There is a false dichotomy, in my opinion, wherein one can only be good by accepting limitations and trusting in norms of modern religion or being an atheist and therefore susceptible to infinite evil.
The tone of all that I have been saying may make my overall impression seem somewhat negative, but I did enjoy reading this play. Though I may not find much worth in Sayer's theodicies, the dialogue was quick and the plot well paced. It is definitely, though, something that is better suited to be viewed or read in a group in order to talk through Sayers's ideas, regardless of whether or not one agrees with them.