This book was not what I expected. I initially picked it up hoping for teen fluff romance, with a bit of screwball comedy edge to it with love-hate/bickering romance (I admit, I'm a sucker for that sort of thing--it's cracktastic to me). To my surprise, while the elements were there, it went beyond that for me and there was a depth to it I wasn't expecting, but was happy to see.One of the critiques I see about this book is one of the aspects I actually ended up enjoying the most: the way it dealt with teen sexuality. It was refreshing to see it explored without sugarcoating it, glossing over it or making it purely about the consequences and lessons. One of the trappings of many teen books is how teen sexuality tends to not have much leeway in how it is expressed and a lot of authors feel like they are talking down to the reader about the subject, not exploring it. I didn't get that from The Duff. It felt real, messy and wasn't just about love and learning. The motivations weren't tidy and always smart, yet it wasn't just illustrated as a disaster for not being such. It dealt with actual pleasure and desires, not always from love or a good place, and it didn't shame it. Which leads to another aspect I enjoyed: how it dealt with name-calling used to tear each other down. Judging/name-calling is used to tear down peers and is quite effective in how it works, especially at that point in our lives. Even the most secure on the surface has those moments of insecurity where it gets to us. It wasn't just limited to being labeled the duff (though this was a major part of it and I enjoy how it addressed it), but the slut-shaming that happened with the girls who were known to get with Wesley (and even Wesley himself). Slut-shaming and name-calling happens at different stages in people's lives, so it was great seeing it addressed at an audience where it really forms its hold and stings the most.But of course, even among the themes, I really enjoyed the characters and how they developed together and separately. I loved sarcastic, closed-off Bianca, thorns and all. I loved arrogant, loner Wesley, with all his flaws. And I loved how they found each other, their interaction and how they developed, together and apart.Overall, I definitely recommend this book to anyone 15+.