Just traveled to NM for a week, and this book had many things you look for in a hiking book: trail accuracy, good driving directions, and a variety of expertise levels. If you want to know the most popular trails in NM, this is the best book I could find.
Now, the reason I didn't give it five stars. I've read many hiking books, so I know what it takes to get from good to great. One problem I had with this book is that many of the trails are focused near urban areas and are the more obvious (and crowded) trails. I'd like to see more variety in some of the wilderness areas (particularly between Taos and Santa Fe on the High Road). The book also could provide more tips on camping areas, but it seems like that's been separated into a different book. I'd like to see a better map of where the trails are in the state. The scaling of the state map is way too small for a state like NM. Finally, the book sometimes takes a trail system and breaks it out into its component trails, treating each trail as if it were its own discreet area. An overview of the major hiking areas would be nice as well (for instance, in the Pecos, where no general orientation is given).
Like I said, this was the best book out there. But being the best doesn't make it excellent.