New character, new music. That's pretty much it. As I've said before, I'm not a big fan of it, but it does fit him. I loved Slow Chemical a lot more, though.
He should use this theme:
On a side note, I'm gonna go back in my family tree and see if I'm related to Jim Johnston (we share a surname, obviously). That would be so cool. Maybe I could get him to write me some awesome theme music.