The main thing you notice about this film if you watch it so soon after reading the book is how very pared down it is. It's only an hour and a half long, but I must say the editing is some of the most impressive I've ever seen. Scenes are contracted, simplified, or omitted altogether, but all the important stuff is there, and both the complexity and the characterisation still comes across very clearly - if not with quite the same depth and texture as Greene manages in the book.
I don't think I have a great deal more to say about the film than I already did about the book, but it was interesting to notice that despite only 9 years passing between the publication of the book and the production of the film, the latter opens with a scrolling text which explicitly states that before the war, Brighton had been a pretty shady place, but it's now all jolly and lovely and not like that any more at all - no guv! I suppose partly this springs from a general desire to leave the past behind in the wake of the war - but I can't help but wonder if the producers were also under a contractual obligation to the Brighton tourist board in exchange for being allowed to film there.
Of course I knew Richard Attenborough was in it as Pinkie, because his picture is prominent on the front of the box. But as the opening credits began rolling, there were some other surprises. Dallow, Pinkie's most loyal henchman, was none other than a sprightly young William Hartnell, while Rose was Carol Marsh - admittedly not a household name these days, but a face I am very, very familiar with after repeated childhood viewings of Hammer's 1958 Dracula, in which she is Lucy 'Holmwood'. The cinematography was also the work of Harry Waxman, later of The Wicker Man, which goes a long way towards explaining why both are so effectively shot.
Definitely deserves its reputation as a cinematic classic - but if you could only fit in one out of watching this and reading the book, I'd say go for the book.