This was the best sequel to The Exorcist they made, and that isn't really saying much. The second one was horrible and the ones that followed were horrible. In fact, I think they were so bad it was instantly remade.
But, this one was decent, it felt the most like an actual sequel to the Exorcist, it was unsettling, it was intelligent, it was pretty memorable in its own way. But it still was a bit too much, not underplayed enough to really feel like the one that started it all.
And, honestly, compared to what we have in the theaters today it is a great film