Back when I was growing up, one of my favorite comics being published was a multiple issue comic that covered all the characters in the D.C. Universe, known as "Who's Who in the D.C. Universe". I still remember the first issue I picked up, somewhere on the far side of the middle, and the character of Nekron, one of the first entries in the comic that I purchased.
So, when I picked up this book, I expected to return to those happy memories. But the "Ultimate Character Guide" is rather... sparse. far from that huge "Who's Who", this book only covers the really important main superheroes and villains, and everything else (and everyone else) is left by the wayside. This, I felt, was far from "Ultimate", and actually seemed rather sparse and anemic after reading the much larger character guide when I was younger. Yes, there might be a hundred or so entries in this book, but it can't come near to the number of interesting, if marginal, characters from the earlier work.
When I hear that a character guide is "Ultimate", I expect it to be the largest, best and most complete, and this particular guide is none of those things. Many characters are left out (like many of the named Green Lanterns, with the exception of Guy Gardiner and Kilowogg and Jon Stewart. And each character is given a short blurb about their abilities and history. While the same short blurb covered their statistics and abilities in the Who's Who series, there was definitely more description of their history and clashes with heroes or villains in the earlier comic series, and far less in this one.
Another thing I had a problem with is the images of the characters, too many seemed rather anime-ized, especially Lightning Lad of the Legion of Superheroes, and while I understand that showing characters as they are currently drawn is important, I also would have liked to see more classic images of the heroes and villains, as I found the anime-ized illustrations stomach-turning.
It's an okay book as far as the DC universe goes, but I would by no means label it ultimate (where is the original Liberty Belle's entry?) in any way, shape or form. I would have liked to see more character history and more than a page per character for the really important characters in the DC Universe. Not recommended, look to earlier works for a more complete comic book history and more on the heroes and villains of the DC Universe.