And Misdreavous vs Murkrow. But everyone compares final evolutions.
These two lines aren't exactly version exclusives or opposites, but seem related enough. They are the two pokemon that evolve with a Dusk Stone, and are absent from either Diamond or Pearl.
So, the usual. Which one has the better design, would beat the other, is the most useful, has the better background, and had the better evolution. Besides which one you preffer for whichiever other reasons.