They are almost like the original 3DS styluses. The only optical differnces to the original ones, as seen in the product images, are the white tip instead of a black one and the missing Nintendo logo. Also the styluses are just a tiny bit shorter than the official ones, which is only noticeable when holding them side by side.
As my New 3DS is already yellowed quite a bit I can't compare the color of the stylus. It looks very white but that's probably the matching tint to when my New 3DS was actually new.
Something else I can't quite say for certain is this: When using my old original New 3DS stylus on the touchscreen (rubbing it around), it's gliding over the screen. When using these replacement ones, I hear a little bit of a scratching noise when going very near with my ear. I don't know if this also was the case with the original one and as I used it over the years it smoothend out. And I also don't know if it is actually scratching the screen just the tiniest amount or it is only the sound. As I don't drag around the stylus on the New 3DS that much, but most of the time just tap the screen with it, it should be absouletly fine for me either way.