Emperor joker v.s. Batmite
Emperor joker v.s. Batmite
As Mungi pointed out: Bat-Mite = "one little bit" of Mxy's own power, whereas Joker = 99.9% of Mxy's own power... So EJ definitely has the power advantage.
That said, this is still a stalemate, imo. Joker may have more raw power at his disposal, but even Mxy himself was unable to kill(or even harm) Bat-Mite -- despite unleashing a blast that destroyed the whole damn company of DC comics. IOW, Joker has no realistic way to 'win'(he's still a n00b with Mxy's power, remember), and neither does Bat-Mite(he's weaker, remember)... Not even a battle of pure attrition will win the day. /shrug