I just helped hook up the propane line to an 80KW generator in Evergreen a few weeks ago. Powered by a 4.6L Ford. Now that's a king-sized residential generator. We had to swap out the propane supply line because the generator sucked all the gas out and the supply couldn't keep up on generator startup.

Personally, I'd prefer LPG over NG simply because the fuel supply is off the grid. We have a 1K gallon tank we keep full all the time even though we use little propane. I know in town there may be more restrictions on propane tanks but I do service a few tanks in the Arvada city limits...mostly 250 or 500 gal. They're with older homes, though, that may have been grandfathered.

I plan to hook up a 8 or 10 KW generator in the not too distant future...as soon as I can afford it. When I have that in place our home will be capable of being completely self-sufficient.