Like most kids, I went through a phase in which I read everything about Greek mythology. Had I read this book during that phase, I probably would have loved it. As I am today, it was okay.
The adventure was decent. The writing was okay (though the moments Percy slipped into present tense were jarring). Okay is the word. I'm not really invested in the main character (or any of his friends) or interested in how the story continues (which, I gather, is something along the Harry Potter lines of "seemingly normal boy with daddy issues saves the world"). People/circumstances were often too convenient and the environmental/animal cruelty bits seemed a little forced.
Honestly, I felt like I was reading the wrong story with the wrong main character from the moment they mentioned the pine tree. (Maybe not the "wrong" story, but one less to my liking.) Perhaps it's because I'm a girl, but Thalia sounded like a character whose story I'd enjoy much more than Percy's. My little brother has informed me that Thalia does enter the story (as a person, not a tree) down the road, but she has a limited role and Percy is still Neo.
I can understand why this series has gained the acclaim and following it has. I would recommend it to younger readers looking for a new adventure series, particularly boys; however, for now, it's not one I'll continue.
PS- We got a bit of North Jersey, but almost no South. What's up with that? Grover would have loved the farmland.