Dukes has better rate stats, yes, but Pence has played more; thus, he has made far greater contributions so far in his career. If you compared VORP's, for instance, Pence's would trump that of Dukes. That's really the true measure of accomplishment, so I'd say Pence has an edge there.
But I have little doubt that Dukes will eventually be a better contributor (insert typical "when healthy" provisos here).