For once, it's nice to have an dev book not full of useless screenshots and blatitudes going beyond 500 pages. This little gem is a delightful stroll through a field I see ignored in most projects too often.
While the authors does not say everthing there is to say about web site optimization, the advice here will be more than enough to out do competitors, to set you a level or two above fellow developers and to show some light on issues that you will probably never find out for yourself unless you do a lot of testing, which you never have time to do, considering the strict deadlines imposed on most projects. Fortunately, Steve Souders has already done this for us.
I love the concept of just doing 14 chapters, each for a given solution, explanining it concisely, giving real world metrics and sticking to the point. Good also that he shows how he did the tests and how he analysis top web sites.
To sum it up, I think this should be a must not only for the front-end engineers, as the book suggests, but also for any developer having to do with the web (asp.net, php, whatever) and architects, project leads, whatever. The book is short and plain, so you have no excuse. It will benefit you no matter what.