He was the oracle of sound writing practice. I studied the example page[1] from his book with his hand-written edits like it was ancient cuneiform. Always the consummate perfectionist in the professional sense of the word, Zinsser was part of the reason I was a technical writer for nearly 15 of my professional years.
I read the language log pretty regularly and they tend to have quality content. Then you got a post like this which says the book is bad and everything about it is bad after skimming it in a book store. An entire review based on skimming and a few out of context quotes does not make a well researched and thought out position on a book. At no point does the author say they actually read the book cover to cover. This is just a rant against being prescriptive in your writing since it is not "the one true way".
I have read On Writing Well and there is a lot of material covered in this book. I recommend the chapters on editing as that was Zinsser's day job.
That example affirms the power of "show, don't tell." Those pages, in the raw, assure the novice or insecure writer that even experts revise and resubmit.
1. http://i.imgur.com/UGWP4vi.jpg