Honestly, the thing that drew me to this book in the first place was the movie. I haven't seen anything about the movie beyond the trailers, but when they're based on books, I always like to read the source material before I see the movie when possible. 
 Overall, I liked The Duff. Bianca didn't always make the decisions that I wanted her to make or that she should have made, but that is what made her character great. For the most part, she's unapologetic about the way she acts and / or thinks and in most cases I thought it was wonderful. I didn't care for the way she treated her friends in certain ways, but Kody Keplinger wrote great secondary characters in Casey and Jessica and their refusal to let Bianca close herself off. 
 Wesley of course is a typical womanizing teenage boy who knows he's good-looking and uses it to his advantage as much as possible. I wasn't surprised by the depth of his character. I liked how he truly became a friend to Bianca even though she wouldn't want to admit it. I think he said that line that best sums up the whole book when he said: "You're just confused...like the rest of us." 
 It's very true and very clear that Bianca is confused for the majority of the book, but I don't hold fault with her for that. It makes the story feel real to admit that you really just have no clue, no idea how the world works, but Bianca kept trying. She didn't give up.