I have the Dickenson propane fireplace and love this thing. It puts out a nice steady heat, sips propane and the fan for it can't even be measured for its electrical draw. These things are so well made that I think any version you get you will be happy with and will work for a very long time. I also like that it uses a double chimney to bring fresh air from outside and then send the exhaust air back out as well so it is a totally closed system.
I've been in LA the last few years so rarely see very cold weather but have use it more on trips in colder climates. I don't know how it would do in sub freezing temperatures but I don't plan to spend any winters in that sort of climate. But even in cold weather dipping below freezing it has kept the van nice and comfortable.