The book feels much like a Gameworkshop yearbook and a bit floppy for casual bedtime reading, but it is well presented with a good number of screenshots, images and maps. There are solid tips for the various Dungeons and Instances which takes you from party composition to gear selection and through to team strategy and loot tables. It's easy to reference, is handily broken down and would be nice to keep on your playing desk next to the mouse.
I was a little dissapointed with the lack of tips, tricks and general suggestions for lower level non instanced dungeons but that would potentially have bulked the guide out even more. That said, a lot of the information is available online so be sure you'll get a use for it before investing in the book.
Overall it is a worthwhile product and I'm sure I'll get many hours out of it, but be sure to flip through it in store to see if you really want this.