I loved Hereditary, and concur that it's easily one of the best horror movies of the past 10+ years for me (along with The Conjuring). I'm a huge horror fan and I was very impressed with it.
I totally get JE's main gripe with it re:the final few minutes of seemingly-rushed supernatural wackiness. I often like it, though, when a movie goes off the rails in such an insane manner (I also really liked Mother! for that, in a different-yet-kinda-similar way).
(btw for anyone else into horror movies that go batshit off-the-rails, I recommend the low budget The Void)