I've been meaning to read this book for years, and fate kindly intervened at DragonCon this year when I won a copy at a panel. The series is so popular that it seems pointless to review it, but I review everything I read here.
I was disappointed, actually. I found the plot predictable, the book overly long considering how little actually happened, and I thought Percy was kind of dumb for not figuring out who was betraying him when it was pretty damn obvious. The characters are flat, and I never got any sense of real friendship between Percy, Grover, and Annabeth.
Still, the story moves along briskly despite its length. Some of Percy's adventures are amusing or clever, and would probably seem a lot fresher if I were eleven years old and hadn't read all the books I've read. There were some really funny lines, too, and I did like Percy's relationship with his father (although his mother was such a marshmallow I found it offensive).
But you know what really annoyed me about the book? Grover, who is a satyr, eats tin cans. Goats don't eat tin cans. Mammals of any kind, whether real or mythological, cannot eat metal and live. Yes, it was played for laughs, and yes, it's in a book about gods that are real so it's not like it's a natural history story, but it's still stupid. And I dislike stupidity in the books I read.