Koh-I-Noor Rapidograph 0.25 mm Technical Pen compared to the Staedtler Mars Professional 0.25 mm Technical Pen

It had been a while since I tried using a Koh-I-Noor Rapidograph Pen. Got this 0.25 mm pen on sale recently and decided to test it using the Staedtler Mars Professional technical pen with disposable refill cartridges as a benchmark. While I normally prefer pen caps that snap on and off the pen body, both technical pens feature threaded caps that can be posted on the back of the pen barrels while in-use. With its maintenance-free design, the Staedtler pen has the advantage as the more user-friendly product since it can be refilled by simply swapping the ink cartridges (each refill change brings a brand new pen nib with its own fresh ink reservoir). The refillable Rapidograph pen requires regular time-consuming and potentially-messy cleanings of the pen nib assembly to remain in good working order.The needle-like metal tube nib of the Rapidograph pen feels scratchier on the gridded index card and Moleskine sketchbook paper compared to the plastic nib encased in a metal jacket of the Staedtler technical pen which glides super smoothly on the same supports.
Close up of these technical pens' nibs. While both 0.25 mm pen nibs lay down fine lines of very similar thickness (with the Rapidograph pen making slightly thinner lines), the Staedtler pen nib looks a bit wider and feels stronger while drawing over a wider range of drawing angles. The Rapidograph pen nib feels rather delicate and tends to skip when holding the pen at sharper angles to the paper. Its performance is very similar to that of the the Koh-I-Noor Rapidosketch pen.The ink of both pens is waterproof once dried, so the sketches can be easily colored with wet media like watercolor pencils and a waterbrush without smearing the inked outlines.