This was the best of three Marrakech guidebooks I bought. I went to Marrakech in September, so I was using the older edition which didn't have some of the newer hotels in it, but this new edition should solve that. The book is light on historical and sightseeing information, preferring to concentrate on more hedonistic pleasures, like dining, shopping, spas, and night clubs. I didn't mind this because there aren't that many great historical sights in Marrakech and I went for a romantic and relaxing vacation, not a history lesson. The restaurant and shopping recommendations were great if you are looking to see the most stylish places in the city. The recommendations are on the high end price wise, but most things in Marrakech (save some hotels) are reasonably priced. All of the entries are written in a witty style and a few are more cautions than recommendations. If you get tired of the grime of the Medina, I highly recommend going out to the new city area of Gueliz. My favorite places from this book were the restaurants Grand Café de la Poste and Kechmara and the stores the l'Orientaliste and Scenes du Lin (all in Gueliz, the last three are all on Rue de la Liberte).
The downsides to this book are 1). The maps are not very good. Although it is very hard to make a good map of the maze-like Medina, the ones in the book lacked so much detail as to be nearly useless (in the Medina, they were fine for Gueliz). Many hotels give away a better, albeit bigger, map for free (bigger being a problem because whenever you unfold a map in the Medina several people will rush over and offer to help you, usually wanting a tip or to take you somewhere you don't want to go). 2). Shopping section could be better organized. Stores that sold rugs were in numerous different categories and there was no way to identify stores in the same neighborhood easily except using the maps at the beginning or the hardly noticeable color coding system.
Also note that this book is primarily used by British tourists in Marrakech and people who see you with it will assume you are British (as opposed to another guidebook I bought that pegged you as an American). No one really cared if we were American or British; it was just an interesting observation.