I used to do tons of ad comps when I was taking advertising assignments. These usually still had tough deadlines,were larger and had to be rendered tighter than storyboards. These always came in a series and frequently had overnight or weekend deadlines as well.
I don't recall the ad agencies or Art Directors on these assignments but each one was part of a series of several ad comps. The first one was done for a Chicago ad agency and the others were done for New York agencies.These were all done using markers on high quality layout paper. For best results I use Bienfang 360 layout paper, but I use the reverse side as the markers work much better on that side.