Yeah I've been around those guys and they've cooked some pretty big briskets and birds in them and never had to add more charcoals to it. They are really easy on the charcoal, an average bag will last you awhile since it really doesn't take that much with them to begin with.
Keeping it out of the wind and watching your time are the 2 most important things...I know my buddy Steve cooks with his all the time and he told me he's tried to get around the time frame they tell you to use and it never worked...he said he's let stuff cook a little longer and it came out over done or tried to take stuff out to fast and it wasn't done enough. They all live on the other side of the state than me so I don't get to hang out with all of them much, they had a big cook out the other night and Steve did ribs in the Orion, my buddy Darrell texted me pics of them all done and said they were the best he's ever ate. I honestly believe for backyard cooking the Orion is the best option around....And yes I told my wife last night I wanted one for Father's Day this year.