I thought it was just okay. The whole time I was reading it, I kept thinking of Harry Potter, and how similar the two are. I loved the mythology element of it. 
 The main character, Percy, is the son of Poseidon and a mortal woman. I wasn't expecting him to be the son of Poseidon at all, and the ending was slightly surprising. While someone you thought was Percy's friend really wasn't, it wasn't the person I was expecting at all. 
 But overall, there really were too many similarities to Harry Potter for me to fully enjoy the book. A group of three kids off to save the world, with a mentor, and a threat to destroy the world, with elements of magic and a special school (or camp) to get training. Percy Jackson is pretty much Harry Potter with a mythology element thrown in, at least based on the first book in the series. 
 The writing is okay- I found it to be somewhat simplistic, but since it's Riordan's 1st YA novel, I'll give him the benefit of the doubt, and hope that the writing in the rest of the series gets better. The 1st-person perspective worked, but I think 3rd-person might have worked a little better. 
 Rating: 2 out of 5. It was a quick read, but the mythology element was pretty much the only thing that saved the book for me.