If you watched the show first, the book is almost an entirely different story. Rhi is a wannabe reporter, there is an AJ, there is a Julia, and her dad is dead. Character names are the same but that's almost it. I'm pleased to report that Tink

doesn't die in this one

 
AJ is a teenager in this version but legally an adult so while iffy not technically anything wrong with it. 

Rhi, to me, is both more and less likable in the book. And her actions make remotely more sense. Neither are better or worse, just different. 

Focusing only on the book now: 

Rhi obviously

has a TBI and PTSD

that makes her 'unsettling' but as a neurodivergent woman I also relate to the aspect of trying to mimic social behaviors and fit in but still having something innately 'off' about you. Also the love of Sylvanian families. 

Her killing the cab driver was really where we see that she uses killing predators as a way to justify and because it's what her dad taught her but she is not an anti-hero or vigilante at her core. The cab driver repeatedly denies her drunken advances and just wants to take her home but she 'sees' the smile of other men in him and kills him anyway. 

There's no doubt that Rhi is an unreliable narrator. We hear only her side and the snippets of what characters say to her. 
I didn't realize this was a series getting into it and I probably won't be reading them since I thought the snippets were a 'jokey' Rhi gets published after all and it's her fictionalized exploits. But I guess it was real. 
I might have been too generous with the rating but it was overall a fun and interesting enough read. 
There is a character who has self-harm scars and threatens/attempts suicide throughout the book and is generally referred to as crazy 

This book is somehow homophobic, transphobic, fatphobic and just generally awful all rolled into one.
I started reading it because I thought the premise sounded good (and it was free on the Kindle store) but it’s trying too hard to be ‘funny’ and just becomes dreadful. There’s slut-shaming, ableism and ‘crying wolf’ about being a victim of sexual assault.
I spent most of the book trying to work out what exactly was happening, the author has clearly tried to be mysterious but just comes off as incompetent most of the time.
The protagonist is a ‘woe is me’, emotionally distant woman who clearly hates herself, and the author did not make me sympathise or empathise with her at all.

The fact all her behaviour is seemly based upon her having experienced trauma as a child (including a head injury) just frustrated me no end, and she comes off as a whiny selfish prat who murders people when things don’t go her way.
Finding out the father was part of an anti-paedophile vigilante gang was probably the only interesting twist, but it doesn’t excuse the rest of the garbage I read.
I could have told you she was going to kill the 19 year old when she asked him to pretend to be dead while they were having sex, and there’s so many red flags and unanswered questions that frankly

it was a chore to read, but I read it solely to be able to write a review to prevent other people having to lose brain cells over reading it.
If I could give it 0/5 I would, but alas I cannot.
Pass me the brain bleach, or put me out of my misery.

A quick read, and the author does a great job at getting inside the brain of a serial killer. Very heavy subjects, and quite fucked up at times (even for a serial killer).