Is it just me? But when a saw a blurb from my favorite author, Marie Lu, I pretty much knew this was going to be a winner. Then when I read the plot and read the first 20 pages I understood why this book is such a big hit. The book was very easy to read, it flowed very nicely. The physical description of the surroundings is unique but very vivid. I also like that it doesn't seem like we are stalling at one moment for a long time while we wait for the narrator to explain or describe. There are just enough details without going overboard. Also, love the dry comedy thrown in.
Then the cover. It is a work of art, literally. I love that it looks like a painting and incorporating the waves into the two girls was such a smart idea. I don't usually like faces on covers, and I prefer them to be pretty plain covers but this one is so well designed to match with the book and to catch the reader's attention, there is no way not to love the cover.