Disclaimer: I have worked as an early stage Venture Capitalist for roughly two years, worked with several Angel investment groups in California and gone to business school. My perspective on the book is based on my investing experience and my time working with high-technology start-ups.
The book is a quick read packed with many very good insights into how to build a small company into a successful one. The main focus is about keeping a very sharp focus on what the company needs to do to succeed -- learn what works, listen to the customer and build an agile organization that can quickly move react but execute flawless when the on point with known customer base. A key point to consider which is missed by many business / management books is that you can not control what your customer base, your competitors and outside economic forces are doing. Change/Chaos = opportunity not a problem. The agile company will maximize the economic opportunity while a large company will try to react but be very late to the party.
An agile company can also position itself favorably for a liquidity event by beating a large competitor to a profitable market; you make the build vs. buy decision for the large company very easy.
I have seen many part of the book put into action successfully and some companies that did not implement the advice; the results are very clear that speed is a competitive tool.
The downside about speed being a competitive tool is that it is very difficult to keep it up for a long period. So, Speed needs to be used to locate and dominate a market to block out competitors. However, other strategies need to be developed in combination with speed and innovation to stay on top...but speed is the way to be the lead company in developing markets.