I have an old homebuilt one close to 40 years old. I bought about a dozen stove insert bricks (the tan ones) and I will line the inside of the stove and the top of the stove with the bricks to help hold heat longer. It makes a noticeable difference.
We run a cylinder stove that I made from a 125 pound wheeled fire extinguisher. Everything packs inside except for the side shelf. It's a heavy beast at 114 pounds all together, but holds heat all night if we have hardwood. When we have to burn pine we pack it full and the first guy to get up and take a leak, fills it back up and we are good to go for the rest of the night.
I broke down and bought a grizzly stove from new england stove works, had planned on using a stove kit on a 35 gallon drum, but the darn drum I bought was crap. Anyone have any experience with one of these? Grizzly Camp Stove-Part Number: 12-CSL