Who is faster, Flashy Flash or Speed-o'-Sound Sonic? At some point in the webcomic, the speed of Flashy Flash's attack is given: it takes a centisecond to perform each attack. I suppose his speed can be calculated if you know the distance of his attacks. I don't know if Speed-o'-Sound Sonic's speed is given or it can be calculated, though it probably has to be over the speed of sound, right?

Who is faster, Flashy Flash or Speed of Speed-o'-Sound Sonic?
While I do like Sonic much better, it's pretty obvious from what we've seen so far: (Manga Spoiler Alert)

1.Flashy and Sonic were from the same ninja village, same ninja class (44th "End Class" or whatever), same generation. Flashy was number 1 from this class.

2.The two ninja dudes (upper classmen from the same ninja school and village), that ate the monsterfication cells, were much faster than Sonic, while Flashy beat them pretty easy 1vs2.

Although Sonic is currently slower, I think that he will catch up at some point and maybe even surpass Flashy.