Zizek is nothing if not an outrageous and wonderful stylist, as anyone whose read him doesn't need to be told, and, to accentuate the positive, this quality is not lacking here in "OwB". Increasingly, however, for the past while, Zizek's books have taken the form of pastiches from previous books of his, and the finished product winds up being something like a series of (interesting) digressions with no main topic to bind them all together. Ostensibly, this is a book that "confronts" Deleuze as the great Frenchman confronted others, and surprisingly, Zizek is able to maintain this confrontation for more or less one third of the book (the first 70-90 pages roughly). It's all downhill from there. I won't even take issue with his reading of Deleuze, which in case you were wondering is basically Badiou's reading translated into Lacanian balderdash--that is, Deleuze lost courage in the face of his "real" insights in Logic of Sense and so capitulated to thoughtless sloganeering with Guattari---no, I'll entertain the thought. The real agony of this book is that people like Dennett and Varela get practically more space than Deleuze himself, especially in the second half, where he literally evaporates--"Like that--Poof! He's gone"---never to be heard from again except in passing references to weird cultural stuff and Empire.
The thing is, I came into this book hoping that Zizek could use all of his wisdom to smash Deleuze into something not-Deleuze, thereby challenging my own tendency to deify Deleuze. That's always a healthy and necessary thing, challenging one's own idols. But alas, it was not to be. This book is about 100 pages too long, and for someone well versed in Zizek I daresay it will be a profound waste of time, as you find him repeating long passages almost verbatim from The Puppet and the Dwarf, themselves repeated verbatim from Welcome to the Desert of the Real. And for Deleuzians--stay far away. You will learn nothing about Deleuze, but, of course, a lot about Lacan, Hegel, and Chesterton if you're interested.
In sum: like the reviewer below I think this is basically worthless and misleading as a book "about" Deleuze. But it is interesting, in places, as when Zizek tries to show how Deleuze is more Hegelian than he thought, leading Zizek into rhapsody about Hegel---very informative about the German, of course; not so informative about the Frenchie.
A highly mixed bag. All I can say is, proceed with caution