I went in to Babadook with no expectation and really enjoyed it. Some horror films are "good for a horror film" whereas I thought Babadook was just good, horror or otherwise.Babadook
Martyrs is insanely good but definitely not an easy watch for a first time viewer to it.Define “good”.
Some of my favourites (Martyrs, Inside, Ghostland) are amazing films, but I wouldn’t necessarily recommend them to anyone.
I do always recommend Sinister for mainstream films.
Recently, Tailgate and Two Heads a creek are a couple of lesser knowns that might go down well.
Then Possessor, if you’re into weird body horror.