My full review is here on my personal website. I'll post a few excerpts here, though:

4.5 out of 5.0 stars

The very worst thing about this book is that I spend most of the time comparing it to Harry Potter because of what tons of people/reviews said about it being “the next Harry Potter,” which it isn’t. Or wasn’t considering the length of time the book has been out. To call this book/series another Harry Potter is to do it a disservice. When compared to Harry Potter, this book fails miserable, but only because it succeeds spectacularly in a different way. Doesn’t make sense? Read the book! :-p

The very best thing about this book is the mythology! I know, Riordan doesn’t always get it right, but that doesn’t bother me one bit! I love this book and happily reread it when I think it’s time.