I really hope I don't step on anyone's toes with this response but I was never really introduced to barbecue, I was "brought up" with it. No... not in the American sense but barbecue none the less.
Now here's the touchy part... It has been said that barbecue actually originated in Jamaica. When the Spaniards came to Jamaica they brought with them their livestock (pigs) which then ran rampant on the island. Once the maroons got a hold of them they started to salt, season and smoke the hogs which was call'd jirking, the starting point for our modern day Jerk. These hogs were smoked by the Jamaican natives and slaves by a means of preserving the meat. Now because Jamaica was THE major trading point between Europe and the "New World" these techniques moved North to the Americas with the slave trade which is when the American form of Barbecue started to take shape.
Jamaica has a huge street food scene we call "Jerk Pans" which sells chicken, pork and sometimes sausage. It's flavored on the jerk side but not what I'd call real jerk. It's usually seared off and then put off to the side to smoke from the hardwood coals and juices dripping onto the hot coals.
So I say all this cuz when I hear the word barbecue I don't think American cue... I think of growing up with smoked chickens seasoned with onion, garlic, thyme, escallion, salt, black pepper, pimento & scotchie... Thats what Barbecue is to me!
Now to actually answer the OP's question... as far as what I've learnt from American Barbecue is a different set of flavor profiles, different combinations, an amazing set of new skill-sets! I love the Brethren and what I've picked up here. Any place you have so many different minds coming together and sharing new things daily will spark new spinoff ideas and the barbecue cycle continues! A great trip IMO!