I have one. It is probably the best gift I've been given. It doesn't take much longer to get up to temperature than my old gas grill, and as you can close the vents to extinguish the fire, you can use a load of charcoal for a couple of cooking sessions.

The ability to use the vents to control the temperature is better than you would think. I regularly cook pork shoulder or ribs for hours at around 220f. By tweaking the upper and lower vents I can adjust the temperature by as little as 5 degrees.

The fact that it is heavy and insulated means that you don't have to keep the flames burning as hot to keep up the temp. That helps keep the meat moist and tender, where in contrast my gas grill would have dried out the food.

They aren't cheap, but every person I know who has tried one became a convert and ultimately got rid of their gas grill.