Propane is nice if you have a big tank, want basically odorless exhaust, and are not concerned about refueling on the playa. Propane has a native motor octane rating around 100, so if you design an engine from scratch to optimize output, you can stuff a lot of compression into it and get good results. And since propane burns so clean and relatively cool, you change the sparkplugs and oil when you lose your nerve, and even then they were likely fine. Finally, propane boils at -44F, so you will rarely have a problem getting a genny to start on the first or second pull even in freezing temps.
That's the good news. Now for the bad news and the reasons I am not a big fan of propane personally.
The first reason is energy density of the fuel. Propane is ~70,000 btu/gal whereas gasoline is about ~105,000 btu/gal, and diesel is ~130,000 btu/gal. Compared to diesel you need almost twice as much propane by volume to make the same power. So you just increased the amount of space required for fuel considerably. Gallon for gallon, propane weighs about half that of diesel (~4.2 lbs/gal compared to ~7 lbs/gal)
The second reason is altitude performance. Because propane is always inducted as a vapor, and it takes a lot of propane by volume to make power, you start "crowding-out" some of the air you could have used for combustion under heavy load. This means a reduction in power potential over the same engine on gasoline. And it means the engine may tend to be peaky at the density altitudes encountered on the playa.
The third reason is refilling ability. You basically will need to either get a single big tank, or use a bunch of 20-lb cylinders and swap them out as needed. Either way, it's a hassle, and the rate of fuel consumption will surprise you. More fuel is not necessarily as close as the burners next door.
Given my choice, I'd be bringing a diesel every time, but you likely don't need the noise, odor, or sheer power (and drama), so my second choice would be a little gas-burner. It's what most bring, and what I bring every year.
Having said all this, there are personal preferences and there is real life. I don't know of any solid reason you couldn't bring a propane genset to the playa and have it work just fine. All of this theory and bench racing goes right out the window when the margarita machine starts cranking-out mugs of icy goodness. Nobody cares what fuel you used or the name/brand on the genset. But of course, if you start have problems and it's not a gas-powered name-brand unit, there will be no end of experts explaining why you are a natural-born idiot. You probably won't find spares on the playa either, meaning a trip to Reno.
I'd try it! But I would have a fall-back plan if power is precious to you. Maybe camp near someone with a bigger gas or diesel set just in case. Think about how much power you need, and for how long. Test the genset under playa loads so you can see how long a tank will last you.
"Give me an underground laboratory, a half a dozen atom smashers, and a beautiful girl in a diaphanous veil waiting to be turned into a chimpanzee, and I care NOT who writes this nations laws"!