We actually discovered sinister because of its neighbor Realm of Darkness. We went to Pontiac with the intentions of going to Realm of Darkness and only bought tickets to Sinister as a package deal. I am so glad we did this because we would have missed out on a totally awesome attraction.
First off, we had to enter the haunted house individually! That alone adds a level of suspense. Again I don't want to give away too many details in case you choose to venture over there. I loved how interactive all of the characters were with everyone. Instead of just jumping out and scaring you, they talked with you and played games with you throughout as well. It was very difficult to tell what was real and what wasn't. The level of detail was amazing from the scenes to the actual characters. And I will warn you, be prepared to possibly get dirty. Myself and a friend of mine came out covered in fake blood. Now this was of course because of how into everything we were so I don't quite think everyone has to worry about this (and don't worry it washes out easily). The end scene was by far the best and most realistic I have ever seen of its kind! Definately well worth it, in fact I'd love to go again if I can find the time.
Cost: $13 per person
Recommendation: This was by far the most interactive Haunted House I've ever been to. I definitely recommend it to anyone who enjoys these sorts of attractions.