I've read many awful stories in my short life time. Stories with hideous plots, with awful writing, with a small resemblance of little things that are neat. Coincidentally, I've written many awful stories so I totally sympathize with Erika Leonard (pseudonym E. L. James). Sympathize, because it appears that James didn't rewrite the original Twilight fanfic before publishing the Fifty Shades Trilogy.
Writing specifics aside, and spoilers, the Fifty Shades of Grey is a romance novel. Hot shot rich entrepreneur seduces college graduate, teaches her kinky ways, they get into an uncomfortable situation, and she leaves him. Fifty Shades Darker explains major tension between the lovers. In Fifty Shades Freed, James packs up the main story line with bumbling children and a new side to the two characters.
I'm really glad I read it, though. It's almost an exercise in editing. Generally speaking, the trilogy is a sin against all literary sacraments. However, I like how James crafted antagonist elements: a hard to bear past, a jealous ex-lover, a ghostly ex-lover, and a very bitter commissions editor/childhood acquaintance. Very well done James.
However, I think I skipped 95% of the “erotic scenes” (IKEA erotica scenes) and kinda glazed through the other aspects of the trilogy. I might, though, read another book by the author. Just to see if she picks up the craft or continues her writing ways. We'll see.
*Edit. If you read the books and have a favorite part you should comment and we can talk about them ;)