Propane injection for diesel pick-up's
 

I have been hearing a lot about the propane injection systems for our diesel engines in pick-up trucks. The only thing I have heard so far is the wonderful and good, and not from the makers of the systems either. This is from the individuals that are putting the systems on their trucks.
So what is the bad side of putting one of these systems on a diesel? Does it make the engine run hotter? Make it blow head gaskets more often? Burn up the valves sooner? Burn a hole in the piston? I am interested in the long, long term affects on the diesel engine. How long have these systems been around, long enough for anyone to know the long term affects?? From all I have heard, the propane gives almost as much more power as a turbo, but costs a lot less. I know you would have to keep refilling the propane, and keep paying for it, but my understanding is you have a switch where you can turn off the propane if you don't want/need it.
Mine is a 1987 F-250 4X4 6.9 liter four speed manual with positive traction.
Anyone out there ever used one of these propane systems, if so, for how long/how many miles, what are your experiences?

Propane injection for diesel pick-up's