My process for reading these was a bit wonky--- I read the first 41/2 in Chinese, then finished the last 1/2 in English, so I don't know how accurate my impressions will be for the first few. However, now that it's over, I'd like to share a few thoughts I had.
First, heretics was definitely my favorite, although you can't really compare the Dune books like you do others. For example, Dune and Heretics felt like the more action-oriented parts, while everything else from children to god-emperor felt more like a buildup to Heretics. Chapterhouse similarly would've been a sort of prequel to the would-be Sandworms. I'm sure Brain's adaptation is decent and all, but I still would've liked to see Frank's version. Especially since Daniel and Marty basically said they were Face Dancers at the end of Chapterhouse.
My favorite thing about the Dune series was probably getting to see how the universe evolved, from the stagnant Imperium, to the madness of Paul's Jihad, and then the almost sleepy state of Leto II's empire, and finally the breaking away from traditions and the excitement and danger of the post-scattering universe. Again, it's really a shame that we didn't get to see Frank's Sandworms--- I would've loved to get some more lore on what happened during the Scattering.
Anyways, I'm going to keep cramming Dune references into my Danganronpa Fanfiction(because yes) and try to find some copies of Brian's books in a library. They can't be that bad.