It's cheap, cookie-cutter, pulp-romance...
...But at least it's GOOD cheap, cookie-cutter, pulp-romance.
It's mostly well-written. The characters are consistent (except one), the dialogue is believable, and the exposition is skillfully woven into the main character's thoughts (always difficult in first-person), rather than the expository info-dump that so many fantasy novels are guilty of. I can occasionally see the hand of an overzealous editor at work, with a few progressions that should take a character an entire chapter being crammed into a page or two in order to keep the book's length down to a size that won't intimidate a reader when they see it on a bookstore shelf, but the plot doesn't suffer too badly for this.
It is an unavoidable fact that the target audience is mostly female, and it shows. It's billed as a romance novel, after all. As such, it starts with a rather formulaic setup. The book centers around a fiercely independent heroine (at least, fiercely independent at first; more on that later) named Feyre. The pronunciation of this name, "Fay-ra," foreshadows her gift from the High Fae Lords at the end of the book a bit ham-fistedly, and it also seems to be a phonetic callback to Fay Wray of King Kong lore, the woman who was able to tame the heart of a beast. Speaking of "taming the heart of the beast, there's a really strong Beauty and the Beast vibe running throughout the first two thirds of the book, right down to Feyre's magical captor having a bestial form whose description even physically resembles the Disney portrayal of the beast.
At the beginning of the novel, Feyre supports her two sisters (who are basically Wednesday Addams and Heidi, or Raven and Starfire if you prefer a more low-brow reference) and her physically and emotionally broken father, a cowardly invalid who lacks the will to do anything for his family. She does this through a profession traditionally thought of as a man's job (hunting). Her ambition, at this point, is to see her sisters married off so she and her father can live in peace and she can spend her life painting: no dreams of romance. Thus we have the standard "I am independent and need no man... until one shows up looking like Fabio, rippling with power, and determined to carry me away to the magical kingdom over which he rules" trope.
When Feyre, on one of her hunts, kills a wolf who turns out to be a Faerie in disguise, the somewhat predictable plot begins to unfold. A self-reliant woman (until she finds out she doesn't have to be), inexperienced in love or sex, is carried away into captivity by a magical Faerie-Beast-Lord, after which the Faerie-Beast-Lord and his all-too-willing captive embark on an Anne McCaffrey style "I love you but you must never find out" relationship, absolutely rife with erotic tension and plenty of chances for Feyre to to end up with soaked thighs by watching her captor unleash bloody and gratuitous violence upon monsters who threaten her (while he manages to cast more than a few predatory growls in her direction, much to her delight) until finally they throw themselves upon each other in a deeply impassioned lovemaking scene which, to the author's credit, manages to be steamy without being base. If that's a formula you like, then that's precisely what you get. I'm not saying it's bad, but acts 1 and 2 offer no surprises.
...And then, there's act 3.
Without going into spoilers, I can safely say that the moment when the three principal characters are interrupted at lunch by a visitor from the Night Court is the moment the plot takes a hard turn, and the reader finds out everything they thought they knew is wrong and nobody is who or what they appeared to be before. From here, the book gets really dark, really quickly, and that's when it gets good! The danger level, the suspense, the emotion, and the eroticism all get turned up several notches at this point as the book grips the reader, refuses to let go, and builds steadily, relentlessly, until it accelerates to an explosive climax that will leave you spent, breathless, and begging for the next book.
I'll admit, it's far from flawless. The first-person perspective undercuts the storytelling a bit, especially since the eyes through which the reader sees this world are the eyes of a woman with an apparent self-debasement fetish (she spends about 15% of the book reminding the reader what a lowly and pathetic creature she is compared to the Faeries among whom she now dwells), an apparent eagerness to sell herself into captivity, and whose taste in men seems to be "if he doesn't threaten to kill me the first time I meet him and then later manipulate me into either captivity or servitude, forget him" (this happens twice in the novel, with two different High Fae Lords). This "all I need in a man is to know he has total power over me" mentality would be believable in a character brought up as a slave, or maybe even one who is jaded from too many indecisive lovers and secretly wants to be carried off over a man's shoulder a la Conan the Barbarian (the works of John Norman, anyone?), but one has to squint a bit to accept it from a character who was portrayed as a mix of Katniss Everdeen and the Once Upon a Time rendition of Snow White at the beginning of the novel.
Still, there are enough roses among all these literary thorns to make it worth reading. Female readers will love it, while male readers won't hate it.