I probably shouldn't be working on my "just for fun" book, but...

I like books about writing and editing. But one I've really been intrigued by isn't a book at all, but a workshop called the Novel Revision Retreat held by Darcy Pattison. But now I guess it really is a book (although I wonder if it would be as helpful as a retreat). I just got the book and am starting it to revise a book that isn't under contract at all, in little corners of time. I'm hoping it will give the book a little extra "oopmph!"

Has anyone else used the book or gone on the retreat? What did you think?