We went once in 2015 and that was more than enough.
I appreciate the fact that the haunt has its own backstory. The attraction is geared more towards young adults than kids, which means that their sets are a bit more extreme than what you'd find at some of the more well known haunts in the area.
At certain points, it becomes incredibly dark. So dark, in fact, that you have absolutely no idea where you are supposed to go. As another reviewer pointed out, there are some stairs that you can hardly see. This resulted in more frustration than fright, as one slip or misstep could have easily sent myself and the surrounding party into an ugly tumble.
On a side note, I ended up accidentally purchasing my ticket for the wrong date. When I attempted to contact someone to adjust/refund the purchase, no one replied. I eventually had to dispute the charge with my bank.
I do feel it's worth checking out at least once, but I wouldn't make it an annual visit.