The Pulsairs not all that big, the Broan is exactly 75% the size. Being narrow may have its advantages too, depending upon available space.
Jim, have you tested the Broan in sub-zero temps, and was 1000W enough to keep it comfy for lounging about, I am not really too worried about night time, as we turn the temp down anyway. The Pulsair is available in 100W too, though at the same cost. On Broans site using their recommended wattage, for the 5.0 you get 155 sf (21'-2" x 7'-4") X 15 = 2325 watts, I realize that they use an 8' ceiling for the height, but also assume the walls are insulated, and a home would have better insulation that the Escape.
170 Wall Heaters -Heaters - Broan
I can't seem to find the Broan without the built in thermostat either, as I would much rather use a digital wall mounted one. We actually have used these heaters in a few projects, especially bathrooms that have inadequate heat, but all the ones we install are 220V (available at Rona), not an option in the trailer.
I know they try to sell the feature, but I like how it draws in one opening, and gets blown out the other, because as all electrical heaters are 100% efficient, it is more about how the heat is distributed that can make a difference.
Stelpro Pulsair Site
These built-in units are designed to be left unattended. I would not worry in the least.
I do plan to install a electric heater, and probably won't decide what I will use until I get to see the interior of the 5.0 again first hand, and see what space is available. Still going to look around a bit more.