I've recently seen this movie again after at least 15 years. The first time it scared me a lot, probably for the weird look in Ivy's eyes and the screaming scenes...
Keep in mind that reincarnation was not a very common subject at the time, and I took it just as many other people, as a poor Exorcist copy. Now, knowing a lot more on the subject, I think it was not too bad given the time it was filmed. The hipnotic regression scene is well done, even though the ending probably can't happen in real life after a regression to a past life.
It was great also watching a young Anthony Hopkins in such role. As always, he convinces you of what he is feeling, and the movie, not being excellent, keeps you interested.
I gave it a 6, considering the good original screenplay (for 1977), and the performances of Anthony Hopkins and Marsha Mason. I must say she seems a little "too dramatic", but that was her style.
If you like Anthony Hopkins and you want to watch a good old thriller, you must see "Magic" too.