Pleased to hear that you're all enjoying the book.
We're working on the official version at the moment, I received the proofs from Midnight Marquee last week and have sent them back a bunch of amendments and revisions - hopefully once they've sorted those out, we'll be in a position to get the American version on sale.
As for differences between the two - the text will be substantially the same (one or two minor changes and corrections, and judging by the proof copy, MidMar have added an American sheen to it with U.S. spellings, some of the British colloquialisms have been softened or changed, etc., but it's largely the same as in the Festival Edition). The book will be smaller, coming in at about 220 pages, and will be fully illustrated (black & white) with a great selection of movie stills, photos, posters etc.
I've still got about a dozen copies of the Festival Edition available.