I remember well in 1975 when in High School a bunch of us went to see House of Exorcism-which we all thought was better than the much overrated The Exorcist. Many years later I got a video of what was called Lisa and the Devil, which I thought was the same film under a different title. However this is NOT the case: Lisa and the Devil and House of Exorcism are two different films. When I saw the Lisa and the Devil version it had nothing to do with the film of my youth, and I was quite disappointed as I found that version quite boring-there was no possessed Elke Sommer or the Robert Alda priest character (although Telly Savalas was marvellous in both versions). Luckily a recent DVD had BOTH versions, so I was able to see the original after many years.
Unlike many of the reviews, I think House of Exorcism was the better of the two, and I am not alone, even though posted reviews seem to like the "Lisa" version better. NOW here comes the truth, which most people don't know. When the original film(Lisa and the Devil)was finished in 1973, it was shown to many distributors-none of whom thought it was any good. Two years later the "redone" version, called House of Exorcism, was made-using much of the same footage of the other film but now having Elke Sommer possessed by the devil and in hospital, and having Robert Alda as the priest who not only exorcises the devil from Elke, but also the house where she had stayed. The same distributors who had shown no interest in the other film now decided to go ahead with House of Exorcism-and the result was that it made millions (at a time when it was still only a dollar or two to see a film). The bottom line here is that millions of people went to see House of Exorcism, while nobody went to see Lisa and the Devil.
So in conclusion I guess that all the distributors, as well as millions of filmgoers, preferred House of Exorcism!