I’ve received samples from my manufacturer of Generic Refills with Swiss tips (0.5 mm) and Japanese gel ink! The Japanese are known for their fine tip gel ink refills which are excellent for drawing complicated Chinese characters. Honestly, I generally prefer ball point pen ink, especially our smooth-writing premium German ink! but these gel ink refills are nice writers. I can see switching out my ball point refill for gel ink if I’m making a sketch or a diagram. These might not be your best choice as your regular refill since they have a limited amount of ink. Most gel ink refills are really fat so that they can hold enough ink. It takes more gel ink to write a page of text than ball point pen ink… I think that is why a lot of people like the gel ink, it can really saturate the paper and makes the line pop with a lot of contrast. Also, the writing experience is different with gel ink which I believe is water-based. Think of ball point pen ink as packing more dye per drop than gel ink; but gel ink can use different dyes because its water-based.
I’ll keep you posted on my evaluation of these Gel-ink Generic Refills.
I would definitely be interested in a gel refill option, even if lifespan is quite short. Assuming cost is reasonable, of course!