Initially, I’d use them for a particular stroke but then moved into doing a spiked shading with them, similar to that used by Frans Masereel in his wood-cuts.
Combined with a hard-tipped outlining pen, they far outstrip the peformance of paint brushes and can adapt to detailed work as easily as they do to bolder strokes and calligraphy.
The first publication I used them in was The Claim in 1982 and then used them regularly with rapidographs for the BRUTE series before dispensing with the tech nibs completely in 1984.
The difference is: with the Rotrings, art becomes like surgery. With the brush pens, its more like foreplay.
Draw the BRUTE! way today: http://www.dickblick.com/products/pentel-brush-pens/#photos