A friend of mine that has to do a lot of technical drawing gave me one of these and I was rather impressed. A couple things really caught my eye:
- The extra dense ink doesn't blead nearly as much as comparable pens. - The felt tip gives it a softer feel than my usual uni-ball Vision Needle. - The lines have less excess at endpoints and inflection points.
All-in-all, the even ink distribution and general cleanliness make great lines for technical draftings or big bold illustrations. I use one whenever I have to fill out a tiny legal form.
The body of the pen warns that you should recap it when not in use - do not take this warning lightly. This thing dries up faster than funding for the arts.