I love Gilded and all (Silvern is my least favorite), but Brazen is either a tie, or my favorite of the entire series.
The third and final book in the Gilded series takes off shortly after Silvern, when Jae Hwa signs a contract with Kud, lord of Darkness and Chaos, to leave behind her family and past life in exchange to save Marc's life. Under Kud's control, Jae Hwa finds ways to save Korea and possibly the world from Kud's potential rule.
There is never a dull moment in Brazen – the book is more action-packed and exciting than the first two books combined (those were exciting in and of themselves, but Brazen is so much more). Jae Hwa's seriously kick butt side also appears as Jae Hwa runs against time to find the Black Turtle orb and returning it to the Heavenly Chest before she loses her humanity or Kud finds the orb for himself. With the contract between Kud branded on her arm, Jae Hwa basically has no one on her side – the Guardians want her head on a platter, Marc is cold and indifferent towards her as expected from the Guardians, and Kud holds the constant threat of harming her loved ones on her head.
But even though almost everyone is against her, Jae Hwa is slowly losing her humanity, and Kud seems to be onto her act sometimes, Jae Hwa still manages to evade revealing her true intentions to the lord of Darkness.
Farley also introduces readers to a little bit of Chinese mythology and history on Jae Hwa's search for the final orb, with plenty of life threatening trials and obstacles that consist of mercury, tombs, and skeletons (plus, drowning). It also promptly demanded me to suggest that Christina pull a Rick Riordan and collide Chinese and Korean mythology together in a spin off series (I just read the Percy Jackson/Kane Chronicles crossover at the time...). Fangirl me squealed when Christina said she loved the idea. (Now I'm really going to start counting my lucky book stars for that to happen.)
In reality, the idea is partially for a selfish reason and I honestly don't want to be done with the entire series. Even though I had a few bumpy occurrences with the characters a few times in Gilded and Silvern, I've actually grown to like Jae Hwa and company. All of them have grown so much in the three books that it's really hard to let them all go and carry on with their happily fictional lives.
I also envy anyone who hasn't reached the final book yet. >_< (But I wouldn't have been able to "shove" the book in a friend's face if I didn't get introduced to the series.)