Really enjoyed this book!!
I knew going in that it was basically Draco/Harry fanfiction.

I liked the differences between CO and HP, the magical phrases were fantastic, I love the idea that the more a phrase is used the more power those words have.
I felt like Baz was Draco and Harry sort of spliced, whereas Simon was movie-Ron, in a bumbling/stupid way too often.
This book was so enjoyable that I sort of want the previous multiple books in the series too. Except maybe not, because the kissing/relationship wouldn't be there, and that's a lot of sexual tension to create and then to slog through.
I liked that after the boys kissed, they didn't really know what was going on between them and Simon was (I think) very realistic in that he wasn't sure what this meant in regards to his sexuality. I did think that Simon "switched sides" about Baz a bit quickly, I think it would have been interesting to have him sort of stew about if he should/shouldn't fight his feelings.
I thought the Lucy portions were a nice way to get some backstory detail, and for us to know about where she fit into the story, but it was also a bit weird, because it turned out that she wasn't visiting anybody and the reader was the only one getting that information. Was just odd for me to be spoken to instead of another character being the receiver of that message.
Also, for Simon to end up with that tail/wings. GAH. But Baz made some "not so fast" comment about removing them--does he like them? Like like them? Weird....

This book, for me, was one of those ones that you get into it and then you don't want to put it down and you're thinking about it and it's distracting to your "real life" responsibilities. I was giddy and had to take deep breaths and I really enjoyed it!
I know it also had some flaws, which I will mention briefly, but I loved it!!!

Flaws:
- it was slow, for many many pages
- there was really minimal plot. I mean, the early HP books were the kids adventuring around Hogwarts and covering a whole school year, but there was building tension and often a mystery that someone was working on. Here, there was sort of this underlying tension about bad stuff that is happening elsewhere and may come to the school. Simon wondering where Baz was was not interesting enough or tense enough to call plot. So really, the plot of trying to find out who killed Baz's mum wasn't introduced for many many pages, and was not really driving things forward fast enough in my opinion.

2018: read some WolfStar and was just desperate to re-read this, wanted to feel such fantastic tension as Rowell puts into the story. Also, there is something wonderful about these characters, for me they are so real and lovable, and I especially like how Baz is in love with Simon but also can see Simon's flaws and still is critical. I love Simon too, but I think Baz is my favorite. And Penny too, this trio is as good as HP for me.