I very much enjoyed it. It's the type of mainstream horror I like. In the same boat as movies like Sinister, It Follows, The Conjuring 1 & 2...it's definitely derivative and heavily relies on jump scares, but there's a very effective sense of eerie dread throughout and the sound design and visuals of these movies are excellent and (especially for a mainstream horror) appropriately nightmarish. So despite not being entirely original, it's definitely effective and I'd pick it over some shlocky campy gore slasher movie any day of the week.