Pros: Well written allegorical story with a light tough. Some nifty "scientifictional" concepts.
Cons: Rather slow. Perhaps dull to the non-Christian-American Community.
It's kind of fun to design your own vision of Heaven and Hell. A lot of people over the years have done it, Dante is the head of this community but others from John Bunyan to Larry Niven have had a crack at it. For the most part these works focus on the Nether Regions giving Heaven short shrift. Hell, it would seem, is more fun to think about. I think part of the fun is consigning those you dislike to creative torments. Dante was in jail when he wrote the Inferno and it shows.
Apparently C.S. Lewis, who wrote our present subject didn't have a nasty list because it's Satan's pad that gets the short end here. The book starts out in a Grey Town where Lewis's unnamed narrator stands in line at a bus stop with a group of rather disagreeable folks. Their destination is above them, literally, the bus takes them to Heaven.
Hell in Lewis's cosmology is a dull place better little considered and quickly left behind. In fact that is the purpose of of the Heavenly Bus Line. Passengers are permitted, if they choose, to visit Heaven, or perhaps just it's front porch. When the passengers alight they discover a bright and alluring landscape and encounter people, usually those they knew in life who try to talk them into making the journey with them "to the mountains" which shimmer in the distance on the horizon. It would seem the damned in Lewis's cosmology may become undamned, if the are willing to pay the price. (Don't remember that from the Bible...)
It seems few do however, only a tiny portion of the residents of Grey-ville even bother to take the trip, there's a comfort zone problem even in Hell. Of those who bother, few are willing to endure the trip to the mountains where, I suppose, God awaits to embrace them. The bus riders are insubstantial as ghosts and the local terrain is hard and immovable. Tiny flower stalks are as immovable as a sequoia and blades of grass are like razors. This changes with time and distance but few of the newly arrived souls are willing to take the pain.
Lewis says the title refers to something in William Blake about the "Marriage of Heaven and Hell". I'm afraid I missed out on Blake for the most part but I gather the title is meant as an answer to this proposed wedding. Another inspiration for the story, as Lewis recounted in his introduction, was a story of uncalled title in an American magazine of what he rather amusingly calls "Scientifiction".
As a story "Divorce" could be more stimulating, most of the action consists of the narator wandering about encountering other passengers interacting with their celestial guides or being instructed by his own (George Macdonald, is the Homer/Beatrice figure here). I don't suppose this is really intended to be a edge-of-your seat action fiesta though.
What it is intended to do is teach, using a device called allegory. This a method of writing that involves the use of objects within the story that act as symbols to make some point, usually a moral one. I'm not going to consume a lot of space here jabbering about my feelings about this over-used literary device other than to say that, like Lewis's colleague and friend J. R. R. Tolkien, (another Inkling) as a general matter I "cordially detest" it. (Those who are interested may consult my review of the movie based on Lewis's "The Lion, The Witch, and the Wardrobe.")
Anyway, Great Divorce is awash in allegory. The entire story is symbolic of something or other. Lewis even says he doesn't propose to be presenting any aspects of any real Afterlife. I'm not sure I'm qualified to comment on the lessons Lewis is trying to present here. I think his points are meant for those who are, in the words of Lewis's pedantic demon Screwtape, "Far along in the Enemy's service" which I'm afraid rather leaves me out. The Big Point, I think is that Salvation or damnation are completely in your hands. He also seems to be talking about clinging to things you don't really like or want in but which are familiar and to a in a weird way, comfortable. Like a hellish job you hate but can't really bring yourself to jettison -- the alternative being too uncertain. (Been there, done that...) Miserable comfort, one of the characters proclaims to his mentor (something like) "We have a nice Theological society down there (in the Grey Town)". I'm sure they do.
Lewis picked up a few nifty concepts from his perusal of those "Scientifiction" magazines. For example, the Grey Town expands as it gains inhabitants, they can wish houses into existence and the all hate each other so they move away from each other. Hell patiently expands for them. The kicker is that the outer regions of Hell are now expanding away from each other at velocities exceeding the speed of light, making the bus stop inaccessible. Take that, Issac Asimov!
The main hit from the the reader approaching this book form a non-religious point of view is that there really isn't a whole lot of action. I don't necessarily demand car chases and gunfire from everything I read (just most movies...) but here the events proceed at a stately, ponderous, even torpid pace. For the reader looking for spiritual ammo. this may very well be a good thing as it allows the ideas Lewis is trying to transmit to enter the mind without having to compete with a lot of noise from the story. Much as a generally dislike the allegorical form, I will admit that Lewis had a talent for it. Usually I feel the curlicues of allegory are noise which jam out the signal of the story, I guess this proves the reciprocal is possible as well.
How 'bout that?