I read this book when I was much younger and loved it. Inevitably though, it was never quite going to measure up today.
It is a young adult read, and as a teenager the fact that some points were skimmed over would have suited me fine. But, as an adult I would have preferred more explanation for some story points (the whole Jennie thing, what happened to everyone once they reached adulthood - they couldn't all be Therapists?), or removal altogether (I don't think the Furies made sense at all, most teenagers won't get it, and it wasn't really necessary for the story). The ending also felt very rushed and a bit too easy.
However I still enjoyed the storyline, the fact that the characters are not perfect, they're not superheroes, they don't have a clue what they're doing, but you're rooting for them anyway. I remember appreciating at the time the fact that the writing was in a slightly more adult style than many other young adult books, and it still is today (swearing, sex references etc).
As an adult I'd give this 2 stars, but I loved it so much as a teenager and have been searching for it ever since, so it gets 3 stars for the happy memories.