I found Jonathan Rosenbaum's writings in the book to be a bit of an acquired taste - but I'd definitely recommend it.
Being a collection of articles written over a thirty year span, it's quite eclectic (don't expect thorough coverage of every stage of Welles's career), some of the older articles are quite dated (like his inventory of seen and unseen Welles work, even though at the time these things were essential, with no-one else going into this level of detail on unseen Welles - although in all fairness to Rosenbaum, he provides up-to-date introductions to most chapters, which recognise some of these limitations), and some of his more conceptual writing is brilliant but debatable, i.e. he makes an impassioned plea against Welles's unfinished work being finished, but I find the piece less than convincing.
What I found a bit grating was the somewhat condescending tone in some pieces, particularly when dealing with Welles-haters; there are passages when he can be less than gracious, and that was quite off-putting.
Having said that, the book is an often thought-provoking set of essays, by turns brilliant and infuriating, and at his best, Rosenbaum opens up new dimensions of Welles's work. I have warmed to the collection, but I would say this: it's not a book that's greater than the sum of its parts. There are some truly outstanding essays in here, but they can be quite patchy. And it's definitely not a book for Welles beginners - for what it's worth, I'd first suggest the seminal This is Orson Welles (edited by Rosenbaum) for Welles's perspective, Berthomé & Thomas' recent Orson Welles at Work for its brilliant research into Welles's working methods, and for sheer readability, Naremore's Magic World of Orson Welles and the two Joseph McBride books are all more smoothly-flowing while being every bit as perceptive as critical appraisals.