I haven't read the books, and watching the film was a lesson in expectations management. Every review I read started with a denunciation of the film's politics, and lamented that the director (a respected artist) was forced to work within the confines of delivering an R rated film (as opposed to an X rated one) and with E.L. James's dialogue and persistent demands for more sex scenes.
Which is fine. On the politics, it's clear enough that Christian Grey is a creep at best whose main seduction trick appears to be having lots of money. He stalks Anastasia Steele, breaks into her house, and disrupts her relationship with both her parents. If she wasn't so dazzled by his dreaminess, she would take out a restraining order and sue him for harassment.
But this is fantasyland. Although it plays to the trope of the aristocratic sadist, 50 Shades is more faithful to the Twilight model of romantic melodrama (the books started life as fanfic). But Edward's fear and repression of sex is here replaced by Christian's fear and repression of love. Which in some ways is an improvement on the original.
But in other ways not. By the end of the film Christian stands condemned in the eyes of Anastasia and the audience, and it is heavily implied that his fondness for BDSM is pathological and caused by some kind of extreme childhood trauma. The idea that those of a kinky sexual persuasion can be perfectly well-adjusted demon-free human beings is sadly missing from E.L. James's narrative. Secretary this is not.
And yet despite all these political problems and the ridiculous dialogue, I do admire Sam Taylor-Johnson and her two leading actors for managing to do so much with the script and portraying female desire so well. Although Christian's issues (described as "50 shades of fucked up" – the only nod to the title) provide the main source of narrative tension, the film would have worked out better with all of that stripped out. 50 Shades as straight-up erotica would need little narrative propulsion beyond Anastasia discovering the joys of sex with a hunky rich guy. One hopes that such a prospect would have been just as wildly popular as the creepy Christian audiences have had to settle for.