I'll venture an answer of "A". Not so much a special sauce, but maybe a combination of leaf source, processing and, well maybe special sauce. A few generalizations, some more accurate than others: The Lakeland companies tend to steam-press their leaf, and sourced from Brazil and Africa, that give them a mature sweetness but for better or worse removes some of the high notes (and tongue bite). Esoterica blends have a certain funky, musty flavor that permeates all of their blends that I have tried. McClelland (and house brands Ashton, Butera, PCCA and some some McConnells) had its zing (some called it ketchup), MacBarens had that weird honey essence that I never liked but many enjoyed. C&D, as noted, has a wide variety of blends, but none have the Lakelands or McClelland signatures - and all seemed to improve with 6 months of aging more than other houses. All of these were somewhat true in my pipe smoking heyday of 1994 - 2010.