I’ll go with the low-hanging fruit: Mein Kampf. I’ve read it, cover to cover. As a piece of propaganda, it’s good. As an example of good writing? Absolutely not (though I will admit I have only read it in translation). Oh, and the whole fascist, racist, and generally shitty worldview of the author that he infuses into the text. And the fact that the author is literally Hitler. You 5-star that book? You’re a Nazi. Period. And as a Jewish person, I don’t look too kindly on them.
It’s also a ripoff of The Last Starfighter, which I think is even mentioned at the beginning of Armada, but it’s still a ripoff. Ender’s Game kind of came first (the story came out, then The Last Starfighter, then the full Ender’s Game novel). Armada manages to rip both off, though, and isn’t a quarter as good as either.