Y'know, I'm not going to "review" it since, if you're a fan of the series, you're going to read it and you'll have your opinion about it. I'll just say that I enjoyed it and I'll be looking for Rick Riordan's next Half-Blood series. I do want to point you to a couple of posts dealing with race in the series:
This post from The Happy Nappy Bookseller is slightly spoilerish, but the incident she discusses happens within the first couple of chapters of The Last Olympian. So consider yourself warned, but do click over there if you've read the book or don't mind slight spoilers. And Jennie's got a (spoiler-free) beef with the audiobook.
And hey, I know there are kids and adults all over the world just chomping at the bit for more about Percy, Annabeth, Luke, Grover, and all the rest. If you're one of them, you should definitely check out Demigods and Monsters: Your Favorite Authors On Rick Riordan's Percy Jackson and the Olympians Series. This collection of essays is edited and introduced by Mr. Riordan himself and includes essays by Sarah Beth Durst, Kathi Appelt, Jenny Han, and Rosemary Clement-Moore (among others!).
A particular favorite of mine is "Why Do So Many Monsters Go Into Retail?" by Cameron Dokey. She examines the many different shops operated by monsters in the series and why our heroes always seem to end up browsing the merchandise, be it waterbeds or garden gnomes.
So if you know someone who just can't get enough of Percy Jackson, check out this collection. And I'd venture to say that it would make an excellent prize for, say, a Percy Jackson trivia tournament or any kind of Percy Jackson program at your library.