This book, perhaps more than any else, is pure libertarian discourse, and - one could say - continues from where Murray Rothbard left off. The basic setup of the book is actually quite ingenious: it goes through generally despised professions or social positions one by one (e.g. the drug pusher, the ticket scalper, the speculator, the middleman) and argues that a representative of each of these serves a valuable market purpose (in the spirit of totally free market capitalism) and that any resentments towards them are not justified (in the same spirit).
Was it good?
With regard to the basic setup and argumentative style and boldness, the book certainly is very good. Whether one subscribes to the arguments being advance, however, depends very much on one's stance towards political philosophy and political economy. In any event, the book should we worthwhile to read regardless, because - like Rothbard's works - it compels one to think an thereby reveal one's position with regard to what is being suggested.
In some cases, however, the argumentation is a little bit forced, like in section seven, where litterers and wastemakers are being argued into being 'heroes' because they, through their actions, underscore e.g. the suggested fact that public places should be privately owned.
The main take-away for me?
Perhaps the main take-away for me has to do with the style of presentation. Namely, by going 'all the way' to the extreme conclusions is an effective way to really test any given argumentative structure and see whether one really subscribes to it or not. This, of course, closely resembles the thought experiment 'method' commonly employed in philosophy.
Who should read the book?
I think that everyone could enjoy the book regardless of whether one subscribes to what is being suggested or not. Of course, this requires a basic interest in political philosophy and political economy, but the text is so accessible that very little prior knowledge is required. Highly recommended.
The book at Ludwig von Mises Institute (freely available): Defending the Undefendable