I hate to admit that I have not used my WSM since I made my drum. I made plenty briskets on the WSM. They had great moisture, rings, and smoke flavor..............but the Drum adds that one flavor profile that the WSM doesn't. It adds that "smoldering beef fat" smell and flavor. The briskets even have that smell that you get when you grill a steak with a good amount of fat on it. The smell can't be mistaken for the smell of wood smoke. So, in the end, you get that extra flavor profile.
I know what you mean about the internal flavor. But personally, I like that balance of the "plain" beef flavor on the inside and then you get hit with the bark, the smoke, and the kinda salty/fatty flavor from the fat dripping and burning on the coals. Another way to get some flavor is to serve it or put in back in it's own foil drippings once you slice it up.
Consider this.......beef broth is very weak, salty foil drippings basically.
One thing I do is save foil drippings. The fat and all. I strain it. Then, those drippings become my injection for future briskets, not all the time. I simply heat it up and inject it as is, no diluting. That makes for some killer flavor.
UDS, Pit Barrel Cooker-Courtesy of Poobah, WSM, 22.5 Weber Kettles-K and DR Stamped, 18.5 Weber Bar-B-Kettle, Weber 18.5 Smokey Joe Platinum, Weber Genesis Silver B, Lil' Chief Smoker, Lodge Sportman Grill, Backyard Fire Pit, Dutch Ovens, Discada Set Up, Turkey Fryer!
BobBrisket Jr.-MUDS, WSJ Silver
My BEST Compliment......"You're a good cooker, Dad!"--My Son.