I still think that Clare should have closed the saga after the third book but at least this City of Heavenly Fire is the best of the "second trilogy". 
 The story is gripping and has a good momentum, all the loose ends are tied up and every mystery is resolved, so that for a fan this is a very satisfying reading. 
 I have only two complains. 
 The first: again new characters are added. I understand that Clare is doing it on purpose, to launch her new trilogy set in the Los Angeles Institute that will be published in 2015 but I personally hate when too many new characters appear, especially at the end of the saga. The action becomes too disjointed and there is no time to become interested in the new stories. 
 The second: the ending. From now on I'm going to SPOILER heavily, so read at your own risk! 
 So: I like happy endings, I really do, but maybe this one was a bit too happy! As it happened with the Infernal Device Trilogy, also here everything in the end worked out perfectly for anyone, in the name of THE TRUE LOVE. Clary&Jace, Magnus&Alec (the more complete and mature couple),Jocelyn&Luke, Isabelle&Simon, Tessa&Jem (yes, again..), Alec&his father, Maia& Bat... 
 The end was more a matchmaking game than a book. 
 I may be a little biased here, since I've hated Simon from day one, but couldn't Clare have at least stuck with the semi-dramatic ending about him? Why had she to bend the rules (again!!), just to put Simon back in the picture? 
 And the only other potentially dramatic event, Jordan's death is somewhat attuned by the knowledge that Maia wasn't really in love with him and is ready to start a new life. 
 At the very end we discover that even the cruelest villain appeared in literature was not so cruel, after all. 
 In the end True Love triumphs and is all very good but I would have appreciated a more realistic ending (nothing too dramatic,,maybe slaughtering Simon would have done the trick...). And I would also have appreciated if the author had stopped after the first "They lived happily ever after" instead of adding a second and a third and...