I found "Uncovered" disappointing. Not for the lack of art from the manga (it's unauthorized, after all - see the fine print on the cover), but for failing to uncover much of anything. Personally, I'm OK with spoilers for volumes that aren't yet out in English, but if you're up-to-date with English releases of the manga, you know 95% of this already. You may even find yourself writing corrections in the page margins, as I did. There's at least one significant contradiction - one statement early in the book (Akito is accepted as the zodiac god because Akira said Akito is the god) is completely overturned late in the book (several zodiac Sohmas knew Akito would be born because they shared a dream of meeting their god). It would have been easy to catch and correct, and I'm not impressed.
There isn't a lot here, either. The print is surprisingly large, and there's a good deal of white space on each page - this is a very thin 183 pages. The text lays out basic facts, but offers scant insight or analysis. I expected more, given all the Japanese material that's available; honestly, I'd send people to Wikipedia before I'd recommend this book. To be blunt, I was left with the impression that the authors were assigned to summarize a series they weren't familiar with, and decided to publish their notes. I bought this out of curiosity, but I'd urge people to get the "Fruits Basket Fan Book - Cat -" instead - while it doesn't cover the full series, it's jammed with art, character profiles, summaries, relationship charts, and new material. You'll get a lot more from the "Fan Book" than you'll find in "Uncovered".