Anyone have any experience with a Southern Burner for greenhouse heating?

I am considering buying one instead of using electric and a small Mr Heater BBQ tank propane heater that I used this year to heat my 8 X 12 Easy Grow greenhouse. Electric rates are expected to double next year. By the way I love the greenhouse. I would recommend it for any beginner who is looking for small greenhouse. It has nice features including a hung door, shelves and a vent opener. It was easy to build. The gaskets were the most time consuming thing. It held up well with the windiest winter I could remember.