This is one of the best books I have read in a long time. Most poststructuralists hedge their bets and stop short of writing anything which amounts to a positive theory of their own; they also stop short of criticising the status quo. Deleuze and Guattari cannot be faulted on either count. Their theory of desire represents an original contribution which synthesises elements of Marx, Freud and Nietzsche with crucial poststructuralist themes such as the critique of the subject, and they provide a set of original concepts which offer potential for all kinds of applications. Their critique of representation and of the imposition of systems of meaning is uncompromising and, unlike so many poststructuralist critiques, does not hold itself back by insisting on the necessity of that which it critiques.
A couple of words of warning are in order, however. Firstly, this is not the book where Deleuze and Guattari develop most of the concepts for which they are famous. Ideas such as smooth and striated space, rhizomes, molar and molecular assemblages, etc., appear in this work but only intermittently. Also, most of the book is about psychoanalysis rather than politics; its central focus is a critique of the Oedipal family and of psychoanalytic practice as an institutional sypport for this particular system of repressive overcoding. In the course of this critique, they also develop a genealogy of capitalism, a theory of coding and a lot more besides, but readers looking to understand their theory would do better reading A Thousand Plateaus.
Secondly, this is a very difficult book - fine for specialists in poststructuralist theory, but a real problem for anyone else. There's a lot of undefined concepts borrowed from other authors and a lot of references to traditions, themes and ideas with which some readers may be unfamiliar. I would advise anyone unfamiliar with poststructuralism to read an introductory text on Deleuze (such as Paul Patton's Deleuze and the Political) and something on poststructuralism (for instance, Structuralism and Poststructuralism for Beginners) before embarking on the original texts themselves. You have been warned!