Hello Jon,
I first read volumes 1 to 3 around 1980, and I read them again a few months ago (compliments of the UK public library service both times).
The books are very heavy going and the theories in them are absurd, to say the least.
So why did I bother to read the books a second time?
Because, as you rightly point out, Jon, they contain useful information and interesting photos.
Consequently, and almost paradoxically, I recommend these books to anybody with an interest in the Pyramid.
As for Pyramidology itself it's become a religion almost, making it nigh on impossible to argue against it.
MJ
We can't all be right, but we could all be wrong ...