Jo Walton once wrote, fairly, that each of Frank Herbert’s Dune novels is about half as good as the one before it. By my math, that makes God Emperor of Dune (#4) about 12.5% of a classic, but it’s still worth reading.
It presents an argument that I think is fundamentally misguided, but it’s worth reading.
It’s about the ruminations of a man who turns into a worm, but it’s worth reading.
I know it’s worth reading because I’m still thinking about it three decades after the first time I read it.