Fat side up, fat side down....yada yada yada. Best thing to do is learn how your smoker cooks and use it ALOT. Every smoker cooks different. It's all personal preference. Experiment, and then do it how you like it - if you can tell the difference. Once you get the internal meat temp above about 180, let it set for about an hour and then learn how to slice it. As stated earlier, the grain changes throughout the meat. Always cut across the grain. If not, just chop it all up and make chop beef sammiches out of it.

Even if you cook it perfect, if you slice it wrong, it will be all stringy......

Also, if you wind up with a bunch of chopped beef, put it in a pot of beans or chili.....

Well as a competiton bbq cooker, I will just reinforce whut other competion cookers responding here have said. Depends on the cooker but always keep the fat cap betwixt the heat & meat!

Now to add another dimension, you ever grill a steak and see them jusices puddle on top? The reason for this is heat creates steam which rises and pushes juices away from the heat source. Hence juice on top.

When cooking fat side up you just force the juices out of the lean to the fat. Then another thing called gravity takes over and them juices and fat just drip over the side taking flavor, spices, etc with them. Because of the heat pushing juices away from the lean there simply is no way for the fat to baste the meat!

And dont flip the briskets, same thing as cookin fat side up. When ya flip that brisket all the juices are just thrown off.

Now with all this said. Cook em the way ya want as each cooker cooks differently. There aint no set "recipe" for q'ing briskets. No time, temps, etc. as each brisket came from a different bovine beast and will cook differently. Briskets are done when they are done. Simple as that.

I cook my brisket fat side down and wrap when its about 165 till its done(passes the poke test)!!!!!

I cook briskets on their side.