I did my first long cook on the Big Green Egg this past weekend, and I did the Boston Butt first. On Friday, I rinsed it, and slathered it with yellow mustard, then rubbed it with TexJoy BBQ seasoning, and wrapped it up in the fridge until Saturday Night. I lit the newspaper in the chimney starter at 11:15, and the temp had stabilized just under 250 degrees by 12:45 (I brought it up to temp slow, per a friend's advice that it's easier to heat the Egg up more, than to cool it off). I used Royal Oak lump charcoal (saving the bag of Big Green Egg brand that I was given with the Egg for when I have the method down, to see if I can tell a difference), and some chunks of hickory from a bag that I bought (not chips, but chunks). I filled the firebox with the new unburned stuff and the hickory, then poured the lit coals from the chimney on top, so that the fire would slowly light the coals below it, to make it burn longer.
I put the Plate-Setter legs-up, and put the drip pan under the grate, and put the butt on at 12:45. I woke up Sunday morning at 4:30 AM to check the temp, to find that it hadn't moved. I woke up again at 8AM, and it stayed exactly the same. I finally opened the Egg at 9:45 (almost exactly 1hr per pound) to check the temp, and it was 195degrees at the thickest part, and almost falling to pieces. I didn't have to open the egg or stoke the fire at all during this entire cook. This is the first time I've done a long cook where the temperature stayed exactly constant the entire time! I wrapped the pork in foil, and put it in a cooler with towels, and it was still hot when I served it for the Cowboys' game that night.
I put a 5lb brisket on directly afterward, and cooked it with the same method, and it turned out great (and had the Texas Meteorite look)! I am thoroughly satisfied with my egg, and I was amazed at how effortless it was to maintain temperature. My experience with offset smokers caused me to run outside to check the temp every hour, which ended up being pointless.