Wow, the dot crawl in that video with composite is far worse than what I see on my TV. It must be the capture cards these people are using. There are visible diagonal lines! S-video is vastly sharper than composite, but composite with a digital comb filter looks much better than what these examples are showing.

There was a time that I preferred the composite look, but I switched to s-video for my PSone and I quickly became used to it. Dithering and fake-transparency have a more pronounced checkerboard pattern, but after seeing the checkerboard, I couldn't un-see it even with composite. The increase in color clarity and sharpness are worth the effort. I just had to turn down the sharpness setting of my TV. Sharpness is just there to artificially boost edge clarity with composite sources, anyway.