I like playing both characters in DMC3, both have good and very fun movelists, the main reason I prefer Vergil is I get to carry my whole kit with me at a time so I don't have to prepare what I want in advance on Mission select or Divinity Statues, I also happen to really like his Darkslayer style, it's a more teleportation based version of Trickstar really.
Oh and I also quite like the character too, unlike in the new DmC (no real spoilers here btw), just finished the Vergil's Downfall DLC and man, he becomes a real ****, makes me like the new Dante in comparison, and I usually hate on the new Dante (well new Dante doesn't act like a **** on Missions 19 and 20, up until then he can just stop making bad puns and gtfo lol).