I'm sorry it took me this long to find this series. This review will apply to the four books currently published, though I see there is a fifth in the works and I cannot wait to read it. 
 At first it seems like your standard thief fantasy. Interesting politics, skilled main character with a dark wit, compelling secondary characters. But then it takes a twist for the superb. It's hard to review this book without giving away the surprise, but suffice it to say that Eugenides is not what he seems. Not by a long shot. Instead he is a lovable, flawed, tortured but not quite brooding, and ridiculously clever character to compete with Kvothe of The Name of the Wind. But he has even more tricks up his sleeve. 
 The author can make the most shocking surprise seem completely believable. It makes for a thrilling read. The first three books especially blew me away. Each time I was so startled I gasped, and yet I felt silly for not seeing it coming sooner. The dialogue is witty and frequently poignant, making even the most minor character seem real. Each of them have their own motives, schemes and plots in the works. But only Eugenides is able to see them all. At times I was heartbroken for him; he is one of the most abused characters I have ever read. Somehow, though, each time his intellect and wit win out over all obstacles. 
 The fourth book is different in tone because there is a different narrator, but I enjoyed Sophos as well. He is a very different main character, more compassionate and kind, but no less intelligent and no less capable of great things than his thief friend. 
 Throughout the series, the exploration of the religion is fascinating. The gods are characters themselves, and the mythology is as much a part of the story and the characters as the actual events. Eugenides manages to be "chosen" by the gods without the feeling that anything is predestined or beyond human control. It comes together as one of the most believable mythologies I've read in fantasy. 
 It's interesting that this is classified as a Teen book. Technically the characters are very young, but it reads much more like an adult fantasy. I still recommend it for teens, especially those that want a more mature storyline and characters. If you want a complex plot and twists you won't see coming, do not miss this series.