I read this as a teenager, and was hugely impressed by it. Growing up in the calcified conservative culture of Catholic Ulster, I felt a lot of sympathy for Heinlein's unsophisticated hero who realises gradually that those who claim to speak for God may actually be speaking for themselves, that a political reality can be deliberately constructed, and that girls are human beings too. Since the 1940 original text is eligible for next year's Retro Hugo for 1941, I returned to it with interest and a little trepidation. I must have been 15 or 16 when I first read it, two-thirds of my life ago; would it hold up?
And actually, yes it does. If anything, Heinlein's portrayal of a theocratic dictatorship ruling a dystopian future America seems a bit closer to the bone in 2015 than it did in 1983. (Though maybe that just reflects on my relative ignorance about the USA in the 1980s.) His thoughts about political messaging are pretty up to date as well, though of course the techniques turn out to be different. I was startled to read Ken MacLeod's assessment of Heinlein's importance to political SF in the Cambridge Companion to Science Fiction, but he was absolutely right; particularly here in the early stages of his career.
Bill Paterson's article on If This Goes On— for the Heinlein Society goes into some detail about the differences between the 55,000 word version of the story, revised in 1953, that we now have access to (in Revolt in 2100 and The Past Through Tomorrow) and the 33,000 word original. The biggest difference is that Sister Maggie, the most interesting character in the revised version of the story, appears to be largely absent from the original version, where our hero ends up with Sister Judith in an epilogue. There is also apparently much less about the Freemasons, and a couple of odd plot adjustments – Judith is horrified, not by the Prophet's sexual advances but by his cynical approach to taxation; and the victorious rebels decide to go for mass hypnotic reorientation of the formerly subject population rather than rejecting the idea as they do in the revised version.
I don't know how easy it will be to get hold of the 1940 text. A couple of things are clear to me, however. First, it's definitely a novella for Retro Hugo purposes; even if it was marketed at the time as a novel, the 2016 rules are clear that 40,000 words is the cutoff and it's a long way short of that. Second, without having read the 1940 version, but bearing in mind what Patterson says about the differences between it and the 1953 version, it's a pretty strong contender and is likely to get one of my own nominations in the Best Novella category. (NB that Jamie Todd Rubin has read the original and found the first half better than the second.)
More thoughts on the eligible short fiction of 1940 in due course.