So it was suggested, by those a decade younger than I, that I partake in this particular film.
While I am not completely disappointed, evidenced by the fact that I was able to sit through an entire viewing without being disgusted by poor plot development, I was nonetheless met with the tired old trope of modern Christian mythology being the centerpiece of the storyline.
In short, if you still cling to such ridiculous beliefs, you will likely find this movie entertaining. Otherwise, pass on this title. It requires at least a rudimentary subscription to demons and afterlifes in order to make a semblance of sense.
I liken it to The Exorcist for that simple fact. Additionally the plot is remarkably the same as that film in that a woman, in lieu of a young girl, is the victim of a demonic possession which requires one man to "fix her". It sucked in 1973 just as it sucked 40 years later.