1. They write too thickly — I write very small, and when I start adding extra details to diagrams it gets even smaller. A line width of about 0.2-0.4mm would be good.
2. The ink bleeds, making the lines thick and unclear.
3. The ink is slow to dry or the tip grows blobs of ink, causing smudges everywhere.
4. The first line drawn is not fully dark, as the ink takes a short distance to get going.
5. The lines drawn are faint unless you press hard (I don't).
I have been given several fancy pens (Parker etc) over the years but they all suffered from problems 1, 3 (blobs), 4 and 5. I'm considering trying a Fisher space pen, but it looks like even the fine cartridge writes rather thickly. Have any fellow Slashdotters found their ultimate pen?"