I'm currently reading Rival by Sara Bennett Wealer, and it's good so far, but it reminds me of that annoying task of coming up with characters with convincing flaws who can be sympathetic at the same time. You don't have a story if the main character is perfect. What's interesting about that? At the same time, if your character is too flawed, it's hard for the reader to care about what happens to her.
As a random soap box moment, I think that characters in books need to be much stronger than characters in movies. It's easier for us to forgive Veronica in Heathers when she colludes with not one, but two terrorists in the making than it is to forgive a character in a romance novel who kisses someone else when she's tipsy and alienates the love of her life. Character development in fiction writing is held to an impossibly high standard. As authors, we don't have a youthful Winona Ryder to distract readers from how repugnance of our character's weaknesses.
Of course, as an avid reader and writer I know what's really going on here: reading is more of an investment than watching a movie. When I read, I become the character I'm reading about, and if I don't like who I am when I'm that person, I feel kind of cheated----unless I can feel redeemed at the end. Characters who do despicable things and need to overcome huge flaws are a reminder to us that even when we think we've hit bottom, there's always hope. That's a wonderful gift and fiction has been giving it to us since the first tall tales were told. The catch is getting the reader to stay with the main character before he or she sees the light.