I can't see how it's fundamentally any different than the MR BUDDY. I keep hearing from people the RV furnaces eat the battery power, and how everybody recommends the MR BUDDY.
The heater in the dodge is one of those vented RV furnaces, combusted propane is piped outside of the van and is fully thermostatically controlled. I like this, set the thermostat and have consistent temperature 24/7. Like the ProCom because it's thermostatically controlled and is portable like a MR BUDDY, I know a window will have to be open to keep safe levels of CO2 inside.
The cheapest thermostat-operated, vented, propane heater will have to be the RV furnaces which haven't changed much in over 30 years. To get them for less than $200, one will have to look inside RV junkyards and on Craigslist for a used one. Because these are made to be built in, the propane inlet is a copper tube; which means one has to adapt it to a standard BBR tank with the appropriate regulator, fittings & know how. I don't know much about propane fittings and OSHA approved flow mediums (tubing and hoses), plus non-common propane stuff is super expensive and hard to find.