A haunt I went to this year had one and I thought it was awesome, very unique. Unfortunately I'm a special case, and apparently it didn't work out great for them. They initially charged $10 per ride, but when I visited later in the season the price had dropped to 2 or 3 dollars per ride, as they were trying to get more people to try it. In talking to them after the season, they said that more people claimed to be claustrophobic than they had anticipated and it wasn't nearly as successful as they'd hoped. They are not offering it this season. Also, when I went through it, the line was made up of mostly macho guys who wanted to prove they could do it. This just limits the demographic of people who will go through it. The ride itself is very cool though.
I believe Tony at Spookywoods has 1 of 2 of them, maybe he can share some of his experiences with it.
Hope that helps