It would definitely be close. The only reason I beat Vergil the first time you fight him in DMC3 is that I stayed away and shot at him . Dante would probably win only because he has Devil Trigger and Vergil doesn't? I only got to the level with Geyron before I had to return it to Blockbuster .
Depends on which version of Dante and Which version of Virgil.
Virgil had like 6 forms: 3 from DMC1 (As the Nelo Angelo) and 3 from DMC3 (The first one was kind of a pushover if you had DT otherwise it was a slugfest, the Second one is where he gets the Light Gauntletes and gets some wicked assed punch and kick moves, and 3 he gets an extra sword, the Force Edge and gets some radical new moves)