I've had the chance to read another Packt Publishing title called Drupal 7 First Look by Mark Noble. I thought I would put down a few thoughts.
I lead Drupal administration and development training on a fairly regular basis and I'm always a little sensitive to instructional books. It's not easy teaching through literature and it's especially difficult to connect the right learner to the right level of literature to be useful to learning. That has been my complaint with many of the Packt titles in the last two years. The top notch authors are very attractive to Drupal learners, but those authors present their concepts with an assumption that readers have the right background. With Noble's book, the intended audience is clearly defined and makes this book more effective that the other's I've read. I have considered including this book as part of the student training material package for workshops I lead.
For the Drupal site administrators who are intending to make the transition to Drupal 7 soon, this will be a great resource. Many of the new admin level features and methods are exposed and the screenshots are useful. The installation walkthrough would be helpful for those who haven't tried it themselves, though it was a little brief. Explanations of the new core modules were great.
The real value comes in the later chapters when Noble breaks down the API changes for developers. Chapter 7 describes some very specific API improvements within Drupal that will impact the work of many developers throughout the community - this chapter is a great guide to updating your own Drupal 6 modules. Theme changes are covered well in earlier chapters, too.
Altogether, I think the book is presented well to the administrator and developer level Drupal users. It would not be useful to new Drupal users as it skirts around some of the fundamentals of the software, but there are other books in Packt's catalog that would be good for that. Drupal 7 First Look can be found here.