Of course DMC3 Dante would win hands down. However I always feel like fights like this were comepletely unfair.
To the arguement of swordsmanship comparison, DMC3 Dante's swordsmanship is impractical and based on the matter of "cool" which allows him to use a sword like a pro despite him having next to no strict training at all. Unless they have a kendo school in the ghetto, DMC3 Dante's swordsmanship should be as lousy and full of holes as DmC Dante. But again; "rule of cool".
Same could be said about gunmanship but who knows.
In terms of power, its like I said before; just because he can twirl a gun around good doesn't mean it equals power. DMC3 Dante shows off most of the time. DmC Dante doesn't. If DmC Dante did show off then this discussion would be treated differently. DmC Dante is based in western realism and his fighting style isn't anime "cool" factoring, but rather the type of strength and fighting style you would expect from a guy on the street who fights demons that no one else sees. He wont fight DMC3 Dante on equal grounds of showing off but rather it'd be like Nero fighting Dante in DMC4; unmatched and just ODante ****ing around.
I always feel like threads like this are just a ploy to wanting to prove how weak DmC Dante is compared to the older Dantes when really we've never seen how nDante actually fights demons in cutscenes. For all we know he might show off while fighting them too but its up to the player to do the showing off instead. (if we use Michellegun201 as a bases of nDante showing off, then he'd stomp DMC3 Dante in the showing off factor since DMC3 Dante doesn't seem to know much ariel manuvors if we base this fight on pure gameplay) But these consideration seems to always fly out the window whenever we have these versus threads, or as I like to call them; "How Can ODante Stomp NDante in this Thread?"