So any reviews from anyone who purchased the new edition with update regarding MP leaving and MM joining?
I have the first one and the one released just before MP left, just wondering if I should? 
if you followed press with the changeover, there's nothing new to learn from the book. it's a good summary if you didn't, though, and it's pretty good at mentioning but not detailing MP's more buffoonish behaviour at the time.
It's also still way too early for getting anything that isn't publicly known. I read the first edition of the book, and you could divide it into two parts essentially: The "past" , which included a lot of interesting dirt, and the "happy-family present", where every band member was content, nothing was going wrong, nobody wanted to leave, bla bla bla .. and a few months later MP leaves the band.
I would think the newest edition of the book will have the same thing. They dare not disclose anything that might get them into trouble, so it will stick to stuff that is widely known.