I had the same question as well. The best haunted house is what I seek.
Just from the suggestion given, looks like
Screamworld may be the best bang for your buck.
It's got different phases in the whole experience, it seems. Two outdoor attractions and three that are indoors. An estimated time to go through all of them is about 45 minutes. Not bad.
Nightmare on the Bayou is the second choice for me. A little shorter, but I keep hearing stuff about it on the radio.
Carnage is the most economical albeit the shortest one of the bunch.
I've never been to any of them, but I may opt for
Screamworld. Yes, I want to be scared shitless!