Certainly the cultural information on cities but are quite relevant advice on hotels and restaurants are sometimes downright bad: The phone numbers are not always valid, the prices indicated are rarely respected. Some prices were sometimes double those indicated.
The plan of the Medina of Fez is simply no one, plan to buy a real map. I quote Backpacker: "Do not be afraid to lead you astray especially" speaking of the Medina. Probably premonitory towards the use of the latter.
The other cards are often incomplete.
Southern Morocco is not treated enough for my taste, so do not hesitate to leave the beaten track but always paying attention!
Prefer the Lonely Planet or Green Guide that are still better and especially more reliable.
And bon voyage!