Eli Bendersky's website I didn't finish reading the book. This is a good measure of how much I "liked" it, I guess. I almost always finish a book, even when it's not very good, and in the rare cases when I put it aside not finishing it, means that I really, really didn't like it. I tried, honest, I read a bit more than a half of it, and tried jumping forward to see if things get better there, but they didn't... Maybe it's because I've read the Hebrew translation ? Don't know, translations sometimes reduce some of the book's quality, but not this much, for sure.
Maybe my expectations were just different. I expected the book to talk about the Enigma cipher, how it is built, how it was developed and how it was broken (in detail !). The reality is, the book talks about sea battles 95% of the time. These sailors caught this submarine here, those sailors caught that ship there, etc etc etc for hundreds of pages. So OK, this is not really about the Enigma cipher itself, this is a historic book describing the naval war, fair enough. Again, the style of this book is so bad that it is hard to follow these historic stories without getting bored.
The author tries to explain how Enigma works in the appendices, but even this is done badly. The first appendix starts with the exlanation of how Enigma was first broken, before explaining how it really works. Reading through it reveals that some knowledge about the cipher is needed. So I go to Appendix 3 (2 talks about an other technique used to break Enigma), which is called "how Enigma works" and from the start it says - "the wheels are set as explained in Appendix 1"... Aargh !
I did gain /some/ useful information from the book. It is obvious that the German mistakes and the successes of Brittish naval troops that caught submarines and ships with valuable information, contributed to the breaking of the cipher no less than the brilliant people at Bletchley park.
To conclude - I think it is a very bad book. You may use it as some historic reference, but it's really not interesting to read. There are much better books (and online references) about Enigma.