I watched Brown do his thing with the flower pots last night and was reminded of my first efforts at smoking some Jerky on a "Lil Chief Vertical Smoker". It was a 3 ft. tall Aluminum Box with a removeable cover, and a built in hot-ring and removeable chip-pan at the bottom. It had 3 levels of racks and did a commendable job on Jerky. It didn't hold heat in worth a darn, but living in the dry desert of SoCal that wasn't an issue as nature helped keep the sucker hot thru the process... but it wouldn't have done a Butt well.
Browns idea has a couple of flaws.
1. In order to 'refuel' the unit you must not only remove the top letting out any heat built up inside, but you must remove the meat being smoked allowing even more cooling to take place. The ideal cooker will maintain a steady heat and if the chef can restrain him/herself from "checking the meat" a lot then it is possible to get that steady heat by not Opening the unit.
2. You can only do one item at a time with that flower pot. One Butt just would not be enough for anykind of family meal (more than 2 people). When I do some meat I do at least two or better yet three Butts and a Brisket or more recently I have been using Turkey Breasts (can't handle the Brisket much anymore).
One of the best units I ever had was an old refrigerator converted to Electric Smoker but still using an electric heat ring and pan (old frying pan) for chips and sawdust. We gutted the refrig., drilled a few air holes in the bottom, and used the opening in the upper back for the exit...baffling it to slow the smoke's travel. The cost was $5 for the unit, and another $5 for the heat ring. The original racks in the refrigerator held the meat and the unit would maintain a steady 190-200 degrees easily. The inside of the unit was white enameled metal, not plastic.
These days I use a cooker/smoker (wood-charcoal fuel)mainly because I have the time to fuss with it a lot during the process.