I'm going to begin this with the caveat that I don't scare easily.
Let's start with the value. I'm a financial analyst so I always begin with value. You spend $20-$30 at any other attraction and go through once. You spend $40 here and get to spend seven hours going through six haunted mazes, multiple scare zones, live shows, and an array of rides. That alone makes it the top attraction in Las Vegas.
The audience varies. I've seen young children all the way up to seniors going through, all having a great time. Their signs recommend no younger than 13, but you know your children better. If they can handle it, bring them. If not, don't.
The actors are top notch. They try their best for the scares. If you act macho, they'll ignore you (perhaps that's the reason for the low ratings?) But they put their hearts into it. The makeup alone is the best in Las Vegas. They look like something out of Hollywood unlike typical Party City costumes.
For the negative--a lot of teenagers when I went. Be smart about it and go when they'll have school the next day. I'm not going to take a star away for something out of their control.