I am a horror buff so not much makes me jump. Perhaps it was the 3D effects, but I thought the movie was good enough that I would definately go see it again.
It had a dry spell in the middle where there were no killings, but it did keep me guessing until the VERY END as to what was going to happen!
My general rule of thumb is if someone dies in the first 5 minutes, it will be a good movie. That has bitten me in the rear a couple of times, but this time it was right on the money.