I liked Cath, but I could not stand how passive she was when it came to Wren. She did me proud when it came to her useless "mother". But not her sister. Wren. Was. Awful. Just a terrible person who treated Cath like dirt and Cath let her. There was no reason or excuses for her behavior and in the end she didn't have to answer for it at all.
And she said crazy things like how much she missed Cath, uh YOU WERE THE ONE WHO KICKED HER OUT YOUR LIFE, DUMBASS! Why did Cath claim acting like a jerk, too? At no point did that happen? She barely said any of the things she needed to say to her sister and she was there for her when she really needed her even though Wren, of course, couldn't appreciate it one little bit and continued to act like a dick. I could go on and on about her but I've given too much away already and there is just too much fodder for ranting. My status updates attest to that. I really didn't understand the purpose of Wren or letting that part of the story play out that way. It did nothing but make me incredibly ragey and drag down what was a decent book. This is not the only authorial choice I didn't understand in this book.
This book is pretty hard to rate for me. I think the parts with Wren, the heinous twin sister of the protagonist, Cath, I would only rate as high as two stars. The rest of the book is a 3/3.5.
For the most part, even though I had some problems with things, outside of Wren I enjoyed this book. There was something unidentifiable about it where I found myself sneaking reading when I could and I haven't really done that with any other books recently.
It was only mentioned once but I was bothered by Harry Potter existing in this world. If Harry Potter existed then the Simon Snow series is pretty much the worst rip-off in the history of all books ever. It doesn't make sense that it would gain such popularity instead of being derided.
The story did a good job focusing on the zeal a fan can have about a particular work and why she would spend so much time writing fan fiction. But I don't think enough of the story was focused on Cath, the fangirl, and her role in fandom other than references to her being a BNF ("Big Name Fan") for her super popular fic to really call the whole book Fangirl. Also, in the end, reading the long swaths of her fic in the text got to be tedious rather than interesting — especially in addition to the between chapter excerpts of the Simon Snow books and fics. Since we don't know the Simon Snow story it was just like reading a secondary story and didn't carry for us, the audience, the aura of what makes fanfic what it is.
Cath was also pretty ridiculous about the fictional story she was supposed to write her for fiction-writing class. I didn't get why the whole thing was so difficult for her and all the excuses she made for not doing it and going back and forth on not completing it period. Then, in the end, the story just skips over the resolution. Why?
I loved her relationship with Levi even though she was super weird about that, too. But we knew she had self-esteem and intimacy issues. I could understand a lot of that. Still, she was strange. I was so glad to read a different YA/NA Heroine who was a virgin but didn't act like it was an albatross around her neck or focused on it at all. [SPOILERISH] When it did happen it didn't become the focus of her life. The second biggest problem I have with this book, however, is that the story skipped over it entirely! There wasn't even a fade to black — it was a black hole. There was discussion of the possibility of her sleeping with Levi. But there was no mention of it ever happening. I'm actually just guessing it happened because I highly doubt she would have been with him the way she was at the end of the book if they weren't sleeping together. For some characters it wouldn't be a big deal, something that doesn't need to be examined because that's the kind of character they are, but that is not Cath. For her it would be huge. She dated Levi for six weeks before they even kissed! (There was one kiss before they were technically together and that was it.) There would have been a significant emotional and psychological aftermath for her and the audience deserved to be taken through the part of her experience. I cannot understand why there wasn't word one about it through the rest of the book. That will bother me forever.
Finally, what was that ending? The story didn't really wrap up at all, it just ended on a couple of excerpts and that's it. It felt unfinished to me.
So I don't know what indefinable thing got me glued to the book in spite of all the problems above. I know there are plenty of people out there that just loved it period. I'd only recommend it with some reservations. Instead I suggest reading Attachments. Rainbow Rowell's first book, which I just loved.