I think kids will enjoy this book more than adults will. I think that there are enough familiar aspects to the Percy Jackson series that it will feel comfortable to younger readers already familiar with Riordan's style, while being slightly exasperating to older readers. I still think it is worth reading and owning.

Side note: Had some confusion with getting this one mixed up with The Alchemyst. Not sure if that is just me, or if there are a lot of similiarities between the two books.