I saw this when it first came out and I was 21. I have never been into the 'horror' genre and went to see it because Clive Revill was in it; someone whose work I liked.
My memory is that I found it formulaic and I wasn't much impressed until stuff started to happen. Then I was involved.
There are some great moments, or they seemed so at the time.
I'm about to watch it on the horror channel, which I don't normally bother with, and am seriously anticipating it.
If I've given you a bum steer, I'll get back to you and apologise.