Me, I liked how there was constantly action and the story was more at a fast pace then the second part. In the second part it was just kinda like here go do this and they don't get caught or into as many fights. Plus, it wasn't as depresing as the second part.
I like the first few books the best (1-4), after that, it just starts to lose a bit of purpose. Like not everything is going somewhere, I feel like JP is stalling for time because nothing really went anywhere after that. There will be build up to an event, then the event will happen, then it will end, and that will be it. It doesn't go anywhere, you know? I felt like the first books had less of that.