I have a non-electric propane heater as my primary heat appliance. It is basically a gas ring inside a tin can. It has a safety valve and a class B stack through the roof. This heater is now in it's third camper and I wouldn't want anything else.
I've seen those fuel oil stoves used but never in a RV. As long as you have a good stack and the heater is in good condition, I don't see a problem, other than a possible odor issue. Most of the fuel and kerosene heaters I've seen in operation tend to come with an odor present. Yours may be one of those that doesn't have a problem. It should be safer than having a catalytic venting into the inside of the camper.
Good luck with the heater and post back when you have it installed. I'd like to see the result.