Well, they both have different fightning positions and styles, so, in general, I suppose they're equal. I reall can't compare the Sparda Twins in fightning. Though, all I can compare to them is their weapon style:
Dante - Rebellion - he is quite good with Rebellion, but on Easy Automatic it is much better to use, becuase the combos are quite often.
Cerberus - In Swordmaster on lv. 2-3 Cerberus is really awesome! But say if I'm not using swordmaster, it's real hard to hit all targets if they are all surrounding you at once.
Agni&Rudra - They are really awesome. Especially when you add Jetstream to them. All levels. But without them too, I guess they're real good.
Nevan - I don't use nevan much, though, I know that Nevan is pretty awesome when you have Air Raid. But other than that, it is much easier to hit all enemies at once with the sweet combos!
Beowulf - It's quite effective, though very slow. Not so good for hitting many targets at once, though Beowulf with the awesome combos, really make it cool.
Vergil - Yamato - Well, the Yamato is real good when coming to hitting air targets. Like for example, those angel thingies. Their defence breaks easily with 3/4 hits with the Yamato. The 'Die' attack when he does a full slice through the targets is very awesome. And so is Judgment cut. So, I don't mind working with the Yamato.
Beowulf - Beowulf with Vergil in DT is wicked Awesome!! But even without DT, it is awesome. I prefer using Beowulf with Vergil than Dante, though.
Force Edge - This weapon was also cool, especially when he throws it in the air and it slices the enemy from around the head. But in general, I prefer Beowulf from all Vergil's weapons.
(BTW, these are only my opinions)
