You had a problem with the Dusty Phillips book ranking on top of Powerful Python. And I can personally guarantee that this book is out of the world good and deserves that spot, if not higher (though the book above by Luciano Ramalho is also very high quality). Here is my review of the Dusty Phillips book, in case you are interested [0].
On your last point, it is certainly best to judge a technical book solely by the content. The problem is : you don't have access to the content until you buy the book. You can of course take a look at the TOC, but doing that for all books in a given field would take a lot of time. It is always nice to have some other indicator that correlates well with quality e.g. average reviews or popularity so that you can reduce the problem space. This is what PythonBooks aims to provide.
[0] http://pythonbooks.org/python-3-object-oriented-programming-...