Siberian Icebox

I'm not sure why the source you quote would insist that catalytic heaters do not produce carbon monoxide. Propane consists of 3 carbon atoms and 8 hydrogen atoms with the structure of CH3-CH2-CH3. Whether in a flame type unit like the Mr. Heater or a catalytic heater, the carbon and hydrogen "burn" to produce heat. The catalyst ensures it does so at a lower temperature, but be sure that the carbon also "burns." Otherwise, you would end up with the catalyst plugged with a block of carbon.

Because both "burn" the carbon as well as the hydrogen, both can create carbon monoxide if there is insufficient oxygen to allow for complete combustion. Both require ventilation and both will need an oxygen depletion sensor to cut off the fuel supply if oxygen levels drop below the point where safe combustion can be assured. Since both also generate water as a byproduct of combustion, the ventilation is also needed to eliminate the moisture build-up that occurs.

Product descriptions for product efficiency:
Camco Olympian RV Wave-3: 99.98% efficient
Mr. Buddy Portable: 99.9% efficient (I could not find any other description except "near 100% efficient).
Both are highly efficient. Both will not produce carbon monoxide if sufficient ventilation is provided but both present a risk if used in a closed area with insufficient ventilation.

When we were in the very cold (4 degree) weather, I set the regular furnace at a low temp (55-60 degrees) at night and ran the Buddy while we were awake. That helped conserve propane and kept us from getting too cold.I had the bathroom vent slightly open. There was some air infiltration under the slide-out. I also had the window in the door open just a tiny bit. Since I had installed a window that could open in the door of our 179, I could do that.

I also agree that it is not wise to run a ventless heater unattended, either while sleeping or away.

The Mr. Buddy heaters produce radiant heat primarily with some convective (as do the catalytic heaters). The glowing ceramic plates in the Mr. Buddy heater perform much as the catalytic mat in the catalytic heaters to ensure virtually 100% efficient combustion. Regardless of the exact means, both combine hydrogen and oxygen to produce water and carbon and oxygen to produce carbon dioxide when there is sufficient oxygen to support proper combustion. When there is too little oxygen, both will not be able to support this process and produce carbon monoxide. That is why the Buddy heaters include an oxygen depletion sensor. I do not know if the catalytic heaters include an ODS or not. The ODS will cut off the fuel supply if the oxygen level drops to 18% or less from the normal 20.95%. This is above the level where carbon monoxide would likely be produced.

The chart on the linked page specifies the type of heat produced by the Buddy heater is Radiant.

When it comes to safety, there is no essential difference between the two. Which one to get is a personal preference.

From the Olympian Wave manual:
recognized before losing consciousnes.

From the Buddy manual: