First of all, I liked the style of the book: It kinda copied the TV-format by always telling the goings-on from the perspective of one character, changing from/within chapter to chapter. There are also pages with photos of the protagonists, maybe to make them more apparent. Wouldn't have been necessary, I think, because this book is definitely not good for someone who doesn't know the series.
In short:
Good buy? - Just buy it if you know (and like) the series.
Content? - Nothing much happens (seeing that it's only a link from season 3 to season 4) but what happens is lovingly written (in very vulgar language and detailed description -- juuust like in the series^^)
Edition? - Paperback, good quality.