Reminds you of the classics...

Rating: 8/10 (15 April 2019)

And that's a good thing, if you like the classics like Rosemary's Baby, The Exorcist or The Omen. It has all the modern updates in terms of visuals, sound design and technology, but it uses the latter in moderation, to its credit. But as a story, in its themes and execution, it's timeless and if you loved those three movies, you're likely to think this one is great as well.
If, on the other hand, you grew up on a diet of Saw, Ring and Paranormal Activity, it's probably a bad thing. I've read the negative comments and reviews of many viewers that seem to have a problem with its pace, themes and the type of storytelling that dominated horror in the 70's up to the 00's.
There's a number of things in this movie that, if you're used to getting everything served in bite-sized chunks (typically literally), may seem out of place or wrong - but they work very well if you accept the movie for what it is.
I think it would be hard to make this movie any better, but I'm sticking with 8/10 because the one valid criticism here is that it *has* all been done before - often. The strong suggestion of a psychological history and the suspense of wondering whether it's all in their heads, the flow of time that leaves out all the mundane and only gets you in the main characters' head space, the supernatural tropes (I won't go into, because that's just spoiling and it's obvious when you see it).
The story is well-told, I think the acting is on point, at least as I understand the characters and the movie looks and sounds amazing. Recommended for horror fans that don't want to stick with modern tropes alone.