I used to be quite a fan of DBZ, but I don't care for it much now.
Yusuke is my favorite of the two characters, but I agree that there wouldn't be much hope for him against Goku, or several other DBZ characters. Just for fun, I would be interested to see how one of the more intelligent YYH characters- say Kurama, Yomi, or Karasu- would fare against Goku, considering that smarts and savvy seem to be the only areas that he was shortchanged in. I think there's too much of a power difference between universes, though.
My personal sense of honor aside, I do love characters who aren't afraid to use deception to their advantage...