Where did you stop reading in the Dune series?

I have noticed that a few users have Dune names. Which always reminds me of the infinite complexity and sheer genuis of the Frank Herbert novels. I read til the last book of the original Frank Herbert series many years ago. Though I have owned Chapterhouse: Dune I haven’t picked it up not sure if I want to yet. It feels like it should be something special. Since I hesitate to read even the books written based on his notes, it seems sacreligious almost. Still I am curious. So I thought I would ask fellow Dune lovers where they stopped and why? Do you ever intend to pick up another one, however far you got?