They're just better plotted. Sorry, not sorry! The early books are charming character studies, but they can feel a bit aimless, like life. The thrillers are meticulously constructed puzzles. Every character, every subplot, every thrown-away line in chapter three pays off by the end. It's immensely satisfying. You can tell she's become a master architect of plot, whereas before she was more of a delightful chronicler of character. The thrillers give you both—the deep characters AND the ingenious, watertight plot. That's a hard combo to beat.