SPOILERS AHEAD!!! 
 So... this was better than I had thought at the beginning. 
 I don't like the main character much, she's practically -if not completely- useless. I don't like Simon much either, not at the middle or at the end of the story, at least. But I like all the Shadowhunter characters and Magnus. I especially like Magnus. So flamboyant and fab, throwing glitter around with his every move. Also, his cat is called "Chaiman Meow". How perf can you be??? 
 But, really, going back to the main character: There was something I found pretty illogical about the whole business with Jace, Valentine and Clary at the end, though. Like, it seemed like Clary realized Jace was her brother (we all knew because if Valentine is your father, and then Jace says he's his father,then duuuh, Jace is at least your half-brother, you empty-headed Clarissa), but then she acts surprised when she finds out that his name is "Johnatan" like her "dead" brother's. So you needed to know his full name to find out you're related even after all the knowledge you got about it before?? *shakes Clary by the shoulders* THINK AT LEAST FOR A SECOND, CLARISSA!! 
 To sum up, my main complaint is that Clary's a very inconsistent character. And sometimes she can be very funny and relatable, but most of the time she's annoying, clueless and useless. 
 Let me add, as a last comment, that I felt like I was reading fanfiction filled with cliches throughout the whole book. Not that I mind, though, because I read a lot of fics when I'm stressed out and this is just as good as that. (Not better, though).