This book took me from being a SQL novice (let alone a PostgreSQL novice) to being able to being able to use PostgreSQL for business apps.
I'm not quite sure why some reviewers knocked it. It has much more content than the FAQ, good examples and a reference section.
One reviewer knocked the reference section, claiming the book was half full of appendices... in fact the reference section is what you most often go to the book for after you've worked through the basic concepts in the first section.
I think the layout is slightly odd - the examples of commands and their results are grouped together in sections that are usually a page or two ahead of the text that explains them. So you spend a bit of time flicking pages to see examples. But once you get the hang of this style it's not exactly the biggest pain in the world.
I think it's a very good book, one that took me from being a SQL beginner yet is still useful as a day to day reference.
Lee