Zenith is an adequate book if you are really interested in playing the character type or if you are a Story Teller. Listed is information on key Zeniths in the Exalted world, information on the caste's role, and, of course, plenty of charms and artifacts.
The book is heavy on filler and those who want more meat might want to just stick to the player's guide. But the book's price does make it a good buy. Just don't feel that you have to collect all the caste books to play the game.
Unfortunately, the book's PDF file was not taken from the original data and has been hand-scanned. The image quality is awful and the pages themselves are tilted. There is, apparently, no index. The book ends abruptly as though there are pages missing.
If you're an ST or an adamant Zenith, then consider picking up this book for its low price.