Fanboy in me wants to say 'EVERYTHING SPICE DUNE FLAVORED IS AMAZING!'
Realistic fan wants to say 'The Frank Herbert books are good. The stuff written by his son and Kevin J. Anderson are okay. The movie is entertaining but not representative of the depth of the book, also lampoons some stuff that is in my mind philosophically important. (Herbert put a lot of work into the book for a reason. He wanted the whole thing to be able to be taken as a gestalt) I think when we are judging the whole series (Excluding canon debate) the important thing is to unfortunately judge each segment of the sandworm separately.
The detailed breakdown is this. Dune as a standalone novel is pretty damn rad. As you already know the characters are unique (Even if their archtypes are not), the setting is rich and vibrant, and Herbert's dedication to evocative description makes the whole thing just a pleasure to read. I give copies of it to friends and family as holiday presents sometimes.
The novels Frank Hebert wrote after Dune are not as focused and tend to get sort of lost in the weeds in some ways. They are worth a comprehensive read I think and I really enjoy them even if I tend to skip around bits when I reread. Overall they take a lot of the consequences of Dune through their 'natural' progression and unfortunately Herbert died before finishing it outright. If you enjoyed Dune, there is a high probability you will enjoy the later novels.
The novels written by his son and Kevin J. Anderson are... Dune flavored pablum. They scratch the itch when the itch arises but I'd rather get the uncut, pure SPICE writing of FH himself. Some of it does read like fanfiction. If you are used to fanfiction, I think it's half decent. If you're not used to fanfiction, I'd leave it alone.
I have watched clips of the movies and read enough about what was cut to have no interest in watching them or the miniseries. In my mind the thing has to to be tackled game of thrones style or pretty much not at all. This next movie attempt is a big gamble with a director who hopefully can translate decades of 'what if' into something both the fandom and mainstream can tolerate if not enjoy.
Meant to post this hours ago, oops!