It's already out. You can buy it on iTunes. I imagine by this point you can just watch it somewhere online for free.
I saw it a few days after it came out and I gotta say I had some trouble sleeping the night I saw it. It's not a scary film in the least, but it diddlys with your head quite a bit if the Disney parks mean anything to you.
I will say that you will most likely not enjoy the film if you have not been to any of the Disney parks or have an understanding of what they are.
I don't really know if I like this film or not. I can't say I didn't enjoy it when I watched it, but, to me, I wouldn't watch it again unless some friends wanted to see it. For me this film was very surreal in the fact that it took the parks and turned it into this awful place that I didn't know anymore.
I only feel this way about the film because I've gone to the parks every year practically since I was born, so I have a distinct connection there.
I wouldn't compare it to Eraserhead after seeing it, but it will definitely creep you out.