system
A chat on subreddit /r/me_irl
human
7, maybe it's placebo but they take the longest to run out, they and don't make an annoying "click clack click clack" everytime you need to use it by pushing a button.

Plus they're the best for drawing/writing with too as the lack of retractability gives the tip extra stability and control.

Not to mention these pens are often cheaper due to the simple design and not needing extra parts like springs, grips and stuff.

Additionally the casing is clear so you can see how much ink you've got left without taking the ink stick out.
gpt
I agree. I have messy handwriting and 7 has better grip on the paper and makes it less messy