The main advantage is that they are very small and you can install them anywhere, using duct to blow the heat in the area of your choice.
It is diesel burner, so it doesn't release all those poisons combustion engine does.
Only worry is CO2 accumulation.
I was also considering the model with coolant heating for heating the water (with heat exchanger), but that would make very complicated project.
If fumes bother you -with small exhaust pipe you can run it any direction you want.
Here is how Sprinter owner reroute the pipe from driver side to passenger side.
For TC I would be tempted to make small coupling on the side and when set - add long pipe above the roof.
