I've read the entire book of Zechariah. It's a prophetic book in the Old Testament, and it uses mystical language to prefigure the arrival of Jesus Christ in the New Testament. Similar to Revelation, it uses highly figurative language to announce the end of the world.
Similar to Preservation, Rutherford attempts, through the use of scripture and exegesis, to place meaning into the challenging OT book. He actually cites copious scripture from Zechariah in order to defend his explanations.
In contrast to Preservation, however, Rutherford seemed to be a lot more desperate in pronouncing the end times. Everything that is in disagreement with him is hypocrisy and Satanism, and this dated allusion to obsolete Aristotelian logic that divides everything into just either black and white left a bad taste in my mouth. This differed little with Leninist literature in that everything that disagrees with Lenin's beliefs was propaganda, even when these disapproving beliefs were actually wiser.
I think the best work of JW literature could be found in Rutherford's work: when he focuses on the scripture instead of attacking the evil British empire, or the Satanic League of Nations, I can respect his work and his beliefs even if I do disagree with him. After all, he cites references. When travesties like Riches happen, however, it seems to me that I'm reading propaganda instead of exegesis: that's not how to defend one's faith.