"ALSO, you people are forgetting to mention the carbon footprint the electric one has: is it's power source a petro power station? Or a coal power station?" Not to mention that first the fossil fuel was converted to electricity, then stored chemically, then re-converted to electricity which is finally turned into work. With a propane powered unit the propane is converted directly, or more directly into work. The fossil fuel is combusted, producing heat which is converted to rotational energy which geared down to drive the machine. The question is which is more efficient? From a consumer, the operator of the the resurfacer, most likely it is the electric version. However, when all losses are taken into account, I suspect the more direct approach may be more efficient.
Just my $0.02