I've programmed in Python before, but haven't used it for a couple of years. I was looking for a refresher, as well as some example applications.
Firstly note that this book isn't an introduction to Python, nor is it a reference. The author makes that clear in the preface, instead referring you to the other titles he has written. Also the book covers Python 3.x. Perhaps those who are interested in earlier versions should get the previous edition of the book. On the other hand while there are some changes between the two versions, reading the book wouldn't be a waste of time if you are interested in Python 2.x
I liked this book in the sense that if I looked up a particular topic, I often found his discussion reasonable and could get some useful idiomatic python code to use.
On the other hand, the author intends this book as a tutorial. When I tried to read through it as a tutorial I just found it falling a bit flat. Also at around 1600 pages I doubt I would have the endurance to read through it from beginning to end.
I guess the main problem with the book is that you are interested in one particular area to use Python, say web development, or interfacing with databases this book would probably have insufficient detail, and you would want a specialist book in that area. Also I found the authors writing style somewhat verbose. Another issue is that those people who want to build a GUI for instance may not be interested in his choice of tool Tkinter.
In conclusion, this book does have some useful information, I didn't really like it. While it is hard to pin down the reasons for my dislike, I guess it is because he tries to cover so many topics, that not all of them are covered that well. Also it is not always clear who the audience is, beginners may find his explanations to terse, whereas those who have some familiarity with python may wonder why he is pointing out the obvious. I recommend people who are looking to develop a particular application in python, instead get a book more focused on their area of interest. Those who are new to python should avoid this book also. Those who are looking for a python 3.x refresher should find a book that's a little less weighty.
It's kind of annoying all those people who have received a free book from O'reilly giving it a five star review. Although they disclosed it, it now makes me suspicious as to how many other five star reviews are given by people who enjoy getting free books, and haven't disclosed the fact.