I'm always 'hawking' them because they came out about a week before my exam. So while I didn't use them extensively, they were great for CTL+F anything that I needed to check quickly. From what I saw, they seem really thorough and are useful to find something rather than wading through hundreds of pages of a text book.
SDN has been a marvelous resource for material, so I'm just paying it forward and recommending things that are useful.