I loved this book...couldn't put it down. I read it's 557 pages in about 4 sittings. The 3rd person point of view didn't bother me at all, and I liked that Riordan continually switches the focus between Jason, Piper and Leo. All 3 characters are great and mold well with the carry-over characters from the Percy Jackson series. I did miss some of the old characters, but I think all of my old favorites will gain more prominent roles and the series progresses. There's also the suspense of not knowing where the lost hero is and the worry over that throughout the book that kept me turning pages. Just a top notch story.
But, I will issue a warning, there is quite the cliffhanger at the end, so if you don't like cliffhangers, wait for the 2nd book to be released next fall. The title of the next book will be "Son of Neptune"...hmmm, wonder who that could be?