Don't knock ADJ customer service. Want to ask a question? They have a toll-free number, I believe. They are good in my opion, way better than average.
Here's my fog machine experience: A filled FogStorm700 lasted me 4 4-hour shows, despite being used quite a bit. Not constantly and not super-heavy fog, but was used considerably. I say this: I used the fog myself for one show, then let a brother-in-law use it for 3 school functions(that's all he borrowed). There was still some left, but not much. Also, everyone I've talked to says the same thing with their fog machines except those big commercial units since there is much more output.
I also hear the same thing with hazers. They seem to be fairly light on fluid consumption.
Still, I'd call ADJ support. Good folks there. I've never been disappointed, and I've talked about my experiences here. It's hard to find good custokmer service these days. While ADJ may not be the absolute best, of the companies I deal with, they are in the top 5 for sure.