I recently became a volunteer for Big Brothers/Bis Sisters. My "Little" is a fan of this book, so I picked it up and was wonderfully surprised with how well done it is. Yes, it is created and read in the shadow of "Harry Potter" so it has that to compete with, and the hero goes on a quest with a guy and girl and they go to a camp for Half-Bloods. Yet still, it's an original book that deals pretty honestly with Greek mythology without giving too much adult info to the young readers, yet at the same time not dumbing it down.
The author, Rick Riordan, creates in Percy a hero diagnosed with dyslexia and ADHD, who is actually the son of Poseidon. He's dyslexic because his minds wants to read Greek, he has ADHD because he sees more then the average person. He also longs to have know his father, to have friends, and find where he fits in. No wonder so many kids like this series, as it hits upon universal wants and experiences, the way "Harry Potter" did.
The kids of Half-Blood are all children of Gods. Some of them stay there forever, others are sent out for quests; that's what most of them want. The "real world is where the monsters are. That's where you learn whether you are any good or not." (pg 170)
One soleful part is when Percy is to fight against Ares, the God of War. He gets nervous, but is reminded "Ares has strength. That's all he has. Eventrength has to bow to wisdom sometimes." (229) (Where have I heard that before...)