Since this is a small pocket book, it would be unfair to compare this guide to a full size travel guide. By nature, the information provided must be limited to the core.
Having said this, when I used this guide for my latest travel to Hong Kong and Macao, I was pleased with the concise information on Hong Kong. The Top 10 tips, recommended restaurants and suggested places to visit were very useful when exploring the city (for example, the list of excellent Dim Sum restaurants). I liked how the HK section was organized by neighborhood, given the size of the city. All pictures and descriptions provided a good indication of what to find and helped me make decisions of how to prioritize my visit. There is also a plethora of useful maps in the book and additionally a convenient pull-out map.
It was therefore quite surprising to realize that the section of Macao was lacking on all fronts. Neither the atmosphere nor gambling spirit of Macao came across in the write-up. The recommendations where to stay and eat seemed arbitrary, and no info about the excellent local bus system was given (just a passing reference)...in a nutshell, information how to explore the city was almost lacking. Luckily, my travel companion had the Fodor's guide for Hong Kong and Macao, and we found Fodor's up to the job in Macao, in particular when it came to describing the different types of hotels and their pros/cons.
Summarizing: You can rely on this guide for your trip to HK, but you need something better for Macao.