I have read pretty much every memoir written by Family members. Fromme's is interesting, truly just recounting the memories of her youth spent with this infamous group of people, and it's relatively well written. She doesn't decry Charles Manson or blame him for her own actions, and she doesn't dedicate a quarter (or more) of her book to born again Christianity, like all those who committed gruesome and horrific murders conveniently do. This is refreshing.
That said, she did remain a follower, and while I do very much agree with her environmentalist stance and maybe to an extent the necessity of fighting the status quo and offenders a little harder, her bias/willingness to overlook the purely evil deeds of her cohort is hard to ignore.
All in all, if you're strangely drawn to understanding what happened and why, and what it was like to have been there, among them all, this book is certainly worth your time.