And in a sense they encapsulate two different styles of adventure writing. In general, Goodman Games adventures exemplify a bare-bones "just the dungeon, ma'am" approach that people stereotype 1E adventures, while Necromancer has a more scenario oriented approach (with lots of dungeon goodness), that seems to typify a more mid-80s, and at times, 2E approach to modules.
Both claim to have 1st Edition style, but one more obviously than the other cleaves much more closely. In that sense, this also illustrates that 3.x has a market for modules and has/had room for both styles.
Though it has just occurred to me...hasn't Necromancer Games stopped putting out modules?