Pirates and Tower of Terror are the rides my 6yo DD seems to talk about most since our trip to WDW. (She was 4 then). She loves the pirates and looked forward to this movie.
I took her this week and we both thought the movie was excellent, even DH did. The pirates turn into skeletons (wicked-looking ones) at certain times in the movie, and there is also quite a bit of violence -- sword fighting, etc. toward the end. My DD only covered her ears during these loud parts, she never hid her eyes. But she did cling to my arm tightly!! She hasn't quit talking about the movie yet -- walking around the house dressed like a pirate! This movie was 2.5 hours including previews.
It really just depends on your child.
There was a brief preview of the Haunted Mansion movie, coming out at Thanksgiving. It looked pretty cool (& scary) too. We will go see it as well.