I liked the first half of "Find You First" much better than the second one. Probably because the beginning of the book was so chillingly plausible that the horror of the situations described felt close enough to touch.
Then, after the Big Reveal (which I'm not going to spoil for those of you who haven't read it yet), the novel and any verisimilitude totally parted ways, and the story became just another over-the-top thriller. A very well-crafted, well-written over-the-top thriller--extremely entertaining, but nowhere near as engaging as it had been when it started off.
The villains, when their identity was revealed, were disappointingly cartoonish, and as such, they lost their edge way before the novel's end.