Neill is very good here. Neill would go on to be one of those few actors with such a range that he can convincingly play the hero to literally the devil incarnate.
Neill has some ear popping monologues with a statue of Jesus. It's so obnoxious that I'm half amazed it wasn't cut. It all strikes me as rather career threatening for an actor and I wonder if any American actor would have done it.
But those scenes do help give this movie a bit of depth.
The first Omen was great because the Thorns weren't sure if crazy supernatural things were occurring, or if they were just crazy. Unfortunately, this one, like Omen II mostly boil down to crazy death scenes.
There's one major annoyance here... why does Damien believe the second coming will be a child*? He literally reads from the Bible. And the producers were well aware that was wrong, considering the display the relevant passages of the Bible.
It's certainly not terrible, and has some effective horror scenes. Looked at simply as a horror movie, it's kind of an oddball, but it works. But considering the seemingly end of time apocalyptic stakes, not to mention closure of the three movie arc, it's lacking, and the world surrounding Damien seems surprisingly small.
* I think the reason Damien decides to kill babies is obvious: the production wanted to do the baby killing thing.
