The n-X refining is to remove paraffin, which clogs the orifices of expensive butane lighters, not remove evil spirits.
When we use lighter fuel, we use 4X Lucienne with great success and typically get strong positive feedback especially regarding our extraction flavors.
Within the mainstream brands typically used for extraction, the gas mixtures are different, typically including propane and isobutane. The propane is added as a propellant, as butane pressure drops off to zero in freezing temperatures. Isobutane is a contaminant, but one with similar properties to butane.
The difference in the water solubility between propane and butane, is enough to give different results and tastes.
We've used a number of brands with good success and within the mainstream brands, I think personal tastes come into play. When using a new brand, I pull the manufacturer's MSDS to determine contents, and spray on a mirror for the sniff, residue test.