First off, I have an overall positive opinion of this book. There are enough strategy/marketing concepts covered so as to make it likely you'll find some ideas that are applicable to your particular situation, whether you're a marketing executive, small business owner, or entrepreneur. For each concept, there are several examples in the form of two or three-page profiles of companies/people that have used the concepts that are explained. The only criticism I have here is that some of the examples were a bit brief in explanation; I would have loved for some of the more interesting strategies to be described in more detail.
As a matter of personal taste, I don't really care for some of the writer's style. For the most part, he's a decent writer. But he begins each profile example in a pattern that goes from that sort of abstract/disjointed position and then chunks down to a point where the reader finally realizes the context and can make sense of the content. Some people love that style. I can enjoy it to a certain extent, but not when it's used extensively, or in this case - exclusively.
Again, this book is educational and can definitely spark the creative side of your business strategy/marketing acumen - if you read it thoughtfully and allow it to. That said, I actually thought the title was a bit misleading. I don't recall a single example in which the "David" in an industry actually toppled a "Goliath" - even if they have staggered them enough to grab some good market share. There is an example of Coke toppling a product released by Pepsi. Aside from that, I don't think any of the giants were killed. That might seem like a minor point, and the stories profiled are certainly still being played out. However, I bought the book with the impression that I'd be reading stories of decisively 'conquering' success. For that reason as well as the writing style and the lack of some insightful details missing from some of the more compelling profiles, I couldn't quite give it five stars.