First, let me say that I enjoy all things Evangelion, and so I bought this artbook sight unseen.
The book's construction is what I've come to expect from Udon Entertainment. The book is big (about 13 by 10 inches), and well-bound. The paper used is high quality, and many of the pages feature glossy illustrations on flat white backgrounds, which makes the images really pop. The book itself looks quite impressive displayed on my shelf.
As for the content, about 1/3 of the pages consist of character art and sketches of the main characters. The other 2/3 features drawings of the Eva Units themselves, drawings of the various Angels, and artists' renderings of scenes from the Eva canon. These scenes range from renditions of the Antarctica expedition to the events in End of Evangelion, so there's a little bit of everything.
Overall, this is an book that I'd recommend. However, if you are expecting an artbook full of character art (like the beautiful image on the cover), you might be a little bit disappointed. I was just a bit disappointed that the various artists collectively got only one page at the end of the book to talk about their contributions, but that's presumably how it was in the Japanese edition. For the more casual Eva fan, or for the fan who is looking for more character art, I'd probably recommend Der Mond: The Art of Neon Genesis Evangelion over this book, as Der Mond focuses more on the characters while this one is more about the Evas and the story.