More Words, Deeper Hole

That depends upon your definition of best" - if popularity is a large part of the equation then Dune wins handsdown - I think it's wretched claptrap that's exactly as ill-done, misogynist, and dull as everything else Frank Herbert wrote.

If you're actually talking about quality, then pick any book by Octavia Butler -Dawn is a good example, it's well done, I wanted to like it, but it was so full of loathing for humanity that I simply couldn't enjoy it and after trying to read the next novel began to actively dislike it. A good friend suggested its one of the better novels about colonialism (from the PoV of the colonized), which I entriely agree with, but that's just as clearly not Butler's PoV.