This is such a well put together book, it might even be the highest quality omnibus in my collection (sorry Final Crisis). There is no gutter loss at all and the pages are sewn loosely that it turns marvelously. It's actually closer to an absolute edition from DC over an omnibus I would even say.
Pro tip from a comic book collector if this is your first omnibus, don't forget to stretch the spine. It prolongs the books life and is good practice for hardcover collections.