Wow. That's not a bad match up. I'm kinda leaning towards Shioon since he seems to learn faster than Kenichi, however, both characters have crazy durability.
Kenichi does look to be more versatile though considering he knows several fighting styles and his precog like seikueken will help him with defense.
As far as speed, which personally I hate to compare from manga to manga, I see them mostly even. Both characters have caught up to speeding vehicles if I remember correctly, but I think Shioon's quick step could give him a slight edge.