Three years ago I modified my EU3000 to run as dual fuel, primarily on gas but alternately on propane. Details of the conversion, including pictures, are on my site:
Also, on www.irv2.com
I posted several articles on the process and results (search for user mswartz, listing all postings.)
I used a conversion system from Carbturbo.com, and since the installation, I've put over 600 hours on the genset (has an hourmeter) with about 200 of that on propane.
My experience is that the unit works well on propane, but in cold weather (ie, propane tanks below 30°F) the genset can experience fuel starvation under load changes, and I therefore usually run the unit on gasoline when I expect the temperature to be below 40°F.
In warm conditions though, propane operation has run the genset well, reliably allowing the 11kbtu Dometic airconditioner to cycle in its normal modes. I leave the economode switch ON at temperatures over 40°F. and OFF below that.
Lately the price of propane has reached record levels here in SE Massachusetts, costing $20 to fill 30LB tanks last week. Certainly gas is more economical for the delivered BTU, and from the standpoint of operating efficiency for this genset works best.
When I'm on a remote site for awhile with the trailer, I can connect to bulk propane tanks and avoid the gas refills, however.