I did enjoy what there was of Buttercup's Baby. I wanted more. It was getting interesting when it stopped.
The author notes/injections gave the book a different feel then the movie. What I liked about having seen the movie before reading the book is that the movie is that the movie is so well cast, that it was nice to be able to imagine the movie characters while reading.
Some of Goldman's interjections did go on for a little long. It was good overall though. Well worth having read it. But in this case, I suggest seeing the movie and then reading the book.