I'd disagree. I grew up with the first five Percy Jackson books (which is weird as I'm British. You'd think I'd be more of a Harry Potter guy in my youth) and I reckoned the author had a much clearer idea of where he was going than Rowling, and really understood Greek mythology (Hades being a tired bureaucrat who doesn't want too much more death as the underworld is overloaded, gives me life).

However, what came after...for the sake of my childhood, I just pretend it ended at book five.