I used the battery ones, which I've had for a while but didn't use much. They are two 18650 rechargeable batteries with an on/off button.
They work good. Get 2.5+ hours out of them and they get nice and warm. Not hot. Not like the fuel ones.
Some places I go to forbid even a lighter in their complex, so these work.
Now... the fluid type...
Coleman white gas. I've googled it, but it all seems pretty generalized. (many say it's the same thing. With tweaks.) I tested it this week.
I think it stinks less. I think they don't get as hot as zippo lighter fluid. But it seems to burn just as long. The Coleman fuel is $14/gal at walfart. The zippo fuel works out to $64/gal.
The internet says I can burn kerosene it these things. I might try some day. I don't think I'm in that big of a hurry to get asphyxiated.
I'll be burning the hell out of the gas ones at work for the next several weeks.