I read a review last month for a $85 butane stove that claimed it was fine down to 20 degrees. Took it out near Flagstaff in 18 degree weather and it just sputtered until the canister warmed under my jacket. But then I see other folks swearing their cheap stoves handle cold all the time. Are these testers actually camping or just doing backyard demos? Has anyone else had a stove fail at real winter temps that got glowing reviews?