I'll base my opinion on fright factor so Jason's stalking just doesn't do it for me. I know his victims just can't seem to move fast enough to escape, but they're idiots. As for hiding in wait for victims, again there's at least opportunity to escape. Dreams on the other hand seem uncontrollable.

So comparing the fear of being chased (I have been) to the fear I've felt in my nightmare, I have to go with Freddy.