Given the high ratings of this book, I was looking forward to reading it. In fact, it is a pretty good book, but difficult to categorize and probably not one I'd recommend for a casual reader.
The general topic of the book is Stalin and the Red Army from the mid-thirties until Stalingrad, and the author seems very well-informed on the topic, and he presents many fascinating details on these topics. That said, there are several things which I did not like much about the book:
1) It is written in a very chatty, discursive style, more like a book-length editorial than a typical narrative history.
2) the text is rather scatter-shot, and while it provides interesting details on the main topics, does not present a very good overview.
3) While the author provides many footnotes, most of them provide additional detail/clarification, but there is very little source citation. Actually, the footnotes were often the most interesting parts of the book, although without having citations it is difficult to know the author's sources.
While I would certainly recommend this book to anyone interested in its topic, I would not recommend it for a casual reader or as a first book about the topic.