Can't comment on the AF much, but I've had two Northlands built in Idaho and then bought an EC 950 2011 built in La Grande Oregon. We travel from Stanley, Idaho mostly in winter. The difference between Northland as EC is dramatic. We have camped at minus 19 degrees and not froze up. We did use the Furnace when it was expected to be minus 19. Absolutely no freeze up. Generally down to 0 degrees we just use the Wave 3 Cat heater I installed. Keeps us toasty warm. The EC has a nice tight seal on the slide out and the mechanism is secure inside. When the temps go below zero at night we close the slide out to minimize area needed to be heated. Works well. I have done some additional insulating and we use a remote thermometer to monitor in the basement and have been very pleased even at minus 19 the basement was above freezing. I may be biased but I believe EC's are a step or two above AF in overall build quality.