Yes Wheelz, it is VERY debatable.
Here's my thinking on #8
As the smoker comes up in temperature and the wood starts to smoke, I want the meat, not fat, to get the brunt of the smoke. Once the smoker is up to temperature, the heating element cycling on and off, I don't think there's a difference between the top and bottom of the meat in regards to the air's temperature. The heat source isn't on long enough and there is no draw of heat up and over at that time.
To check this theory, I placed a large pan of water in the smoker, put a temperature probe under and another over the water. Once the smoker was up to temperature, 20-40 minutes, the difference between the probes was less than 5 degrees and didn't change as the heating element cycled on and off.
So, why have the fat side up? So gravity will baste my brisket. Why have the fat side down? To protect the meat from the harsh heat source. But since I've now been able to convince myself the meat isn't being blasted by heat other than the start of the smoke, and that the muscle is able to soak up the direct smoke at the start of the cook, I'll endorse the fat up theory. All my opinion and we know what it's worth when weighed against the experience of others on here; about nada! Ha!