I still remember reading White Cat, and trust me I went fangirl over that book! I have always loved the concept behind this series, it's so unique, and it's so remarkably well done! I love Holly's Modern Faerie Tale books...but the Curse Workers, they blow my mind! I absolutely LOVE THEM! And this one...Black Heart is by far my favourite of the trilogy! The perfect ending to an incredible trilogy! :D 
 I absolutely love Cassel. He just gets better throughout the trilogy, and I always just want to give him lots of hugs. He's had some rough times, and I always feel bad when he's trying to deal with stuff that he's done or thinks he's done when it isn't really his fault. He was awesome in Black Heart though! Seriously clever, and probably at the most honest we've ever seen him...which, let's face it for Cassel is quite the feat! :P 
 Overall, Black Heart was amazing! There was a lot of relationship/friendship drama, and some extreme stuff (I'm being overly general here, but I don't want to spoil anything :P) that constantly keeps you reading. I barely put this book down, and I only stopped reading because it was late at night and I was falling asleep. If you start it early don't be surprised if you finish this book in one solid read, it's seriously addictive! 
 If you haven't started this trilogy yet...you need to! It's one of my favourites, and since I've just finished the final book in the trilogy, I can also tell you that this is one of those trilogies that will leave you satisified from the beginning to the end. The ending is a bit open-ended, but it settles everything that you feels NEEDS to be settled, which is always awesome...plus, the ending of Black Heart was perfect! I honestly don't think I could have thought of a better ending than what was there! Holly Black has definitely hit the perfect score with it! I'm seriously so happy that it ended the way that it did, and I hope that everyone else will love it as much as I did! :D